Optical system and imaging apparatus

ABSTRACT

An optical system includes two imaging optical systems disposed symmetrically with each other; two holders to hold the imaging optical systems; and two shaft members including a first shaft member and a second shaft member. The first shaft member is held by the first hole of the one holder, and the second shaft member is held by the second hole of the one holder. The first shaft member is disposed in the second hole of the other holder with a movement of the first shaft member restricted in each direction perpendicular to a direction in which the first holes are opposed to the second holes. The second shaft member is disposed in the first hold of the other holder with the second shaft member movable in only a certain direction within a plane perpendicular to the direction in which the first holes are opposed to the second holes.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is based on and claims priority pursuant to 35U.S.C. § 119(a) to Japanese Patent Application No. 2018-053348, filed onMar. 20, 2018, in the Japan Patent Office, the entire disclosure ofwhich is hereby incorporated by reference herein.

BACKGROUND Technical Field

Embodiments of the present disclosure relate to an optical system and animaging apparatus incorporating the optical system.

Background Art

Spherical imaging systems are known that generate an image within asolid angle of 4π steradian by combining images captured by two imagesensors. Such spherical imaging systems include two imaging opticalsystems having the same configuration in which a wide-angle lens with awide angle of view of 180 degrees or more and an image sensor thatcaptures an image formed by the wide-angle lens are arranged.

Such an imaging system equipped with a plurality of optical systems asdescribed above has the following difficulties when mounted on animaging apparatus. First, when a plurality of optical systems isincorporated into a single lens barrel, the lens barrel tends to be of acomplicated structure and be difficult to manufacture. Further, it isalso difficult to incorporate optical elements constituting the opticalsystem into the lens barrel. Further, when a plurality of opticalsystems is incorporated into the lens barrels each having a differentstructure before combining the lens barrels, such lens barrels eachhaving a different structure and peripheral components need to bepreliminarily prepared, which adversely increases the number of kinds ofcomponents, time and costs to manufacture the components. By contrast,when a plurality of optical systems is incorporated into each of thelens barrels having the same structure before mounting the lens barrelsonto a base, the number of components increases and results in highercost. What is worse is that an additional component needs to be disposedbetween the lens barrels, which is disadvantageous from the viewpoint ofthe assembly accuracy between lens barrels.

When a plurality of optical systems is combined to constitute an opticalsystem, there are demands for proper orientations and relative positionsof the optical systems to be easily set and also for sufficient strengthto be obtained so as to prevent displacement of the positioned opticalsystems.

SUMMARY

In one aspect of this disclosure, there is provided an improved opticalsystem including two imaging optical systems disposed symmetrically witheach other; two holders including one holder to hold one imaging opticalsystem, and other holder to hold the other one imaging optical system;and two shaft members including a first shaft member and a second shaftmember. The two shaft members are disposed between the two holders. Eachholder has a first hole and a second hole. The two holders are disposedsuch that first holes are opposed to second holes. The first shaftmember is held by the first hole of the one holder, and the second shaftmember is held by the second hole of the one holder. The first shaftmember is disposed in the second hole of the other holder with amovement of the first shaft member restricted in each directionperpendicular to a direction in which the first holes are opposed to thesecond holes. The second shaft member is disposed in the first hold ofthe other holder with the second shaft member movable in only a certaindirection within a plane perpendicular to the direction in which thefirst holes are opposed to the second holes.

In another aspect of this disclosure there is provided an improvedimaging apparatus including the above-described optical system and twoimage sensors to form images captured by the two imaging opticalsystems, so as to combine the formed images to generate one image.

BRIEF DESCRIPTION OF THE DRAWINGS

The aforementioned and other aspects, features, and advantages of thepresent disclosure will be better understood by reference to thefollowing detailed description when considered in connection with theaccompanying drawings, wherein:

FIG. 1 is a left-side view of an imaging system that constitutes animaging apparatus according to an embodiment of the present disclosure;

FIG. 2 is a rear view of the imaging system in FIG. 1.

FIG. 3 is a top view of the imaging system in FIG. 1.

FIG. 4 is a perspective view of a composite barrel including an imagingsystem.

FIG. 5 is a rear view of the composite lens barrel in FIG. 4.

FIG. 6 is a left-side view of the composite lens barrel in FIG. 4.

FIG. 7 is a top view of the composite lens barrel in FIG. 4.

FIG. 8 is a bottom view of the composite lens barrel in FIG. 4.

FIG. 9 is a perspective view of two separate lens barrels thatconstitute the composite lens barrel in FIG. 4.

FIG. 10 is a left-side view of the two separate lens barrels in FIG. 9.

FIG. 11 is a top view of the two separate lens barrels in FIG. 9.

FIG. 12 is a bottom view of the two separate lens barrels in FIG. 9.

FIG. 13 is a front view of one of the two separate lens barrels in FIG.9.

FIG. 14 is a rear view of one of the two separate lens barrels in FIG.9.

FIG. 15 is a front view of a base frame constituting one of the twoseparate lens barrels in FIG. 9.

FIG. 16 is a rear view of the base frame.

FIG. 17 is a perspective view of the base frame as viewed from the backside.

FIG. 18 is a perspective view of separate base frames of the two lensbarrels.

FIG. 19 is a perspective view of a base frame of the front-side lensbarrel with two shaft members used for positioning attached.

FIG. 20A is a cross-sectional view of the base frame without a shaftmember mounted, taken along line XX-XX in FIGS. 15 and 16.

FIG. 20B is a cross-sectional view of the base frame with a shaft membermounted, taken along line XX-XX in FIGS. 15 and 16.

FIG. 21 is a cross-sectional view of a part of the lens barrels takenalong line XXI-XXI in FIG. 5.

FIGS. 22A and 22B are cross-sectional views of a positioning mechanismon a main reference side.

FIG. 23 is a cross-sectional view of the part of the lens barrels inFIG. 21 with a front cover of an imaging apparatus mounted.

FIG. 24A is a cross-sectional view of the base frame without a shaftmember mounted, taken along line XXIV-XXIV in FIGS. 15 and 16.

FIG. 24B is a cross-sectional view of a base frame with the shaft membermounted, taken along line XXIV-XXIV in FIGS. 15 and 16.

FIG. 25 is a cross-sectional view of a part of the lens barrels takenalong line XXV-XXV in FIG. 5.

FIGS. 26A and 26B are cross-sectional views of a positioning mechanismon a sub-reference side.

FIG. 27 is a cross-sectional view of the part of the lens barrels inFIG. 25 with the front cover of the imaging apparatus mounted.

FIG. 28 is a cross-sectional view of the positioning mechanism on thesub-reference side in an error with the shaft member assembled in areverse direction.

FIG. 29 is a rear view of the base frame with a front rear framemounted.

FIG. 30 is a cross-sectional view of the lens barrels taken along lineXXX-XXX in FIG. 29.

FIG. 31 is a perspective view of the base frame and the front groupframe taken along line XXX-XXX in FIG. 29.

FIG. 32 is an enlarged cross-sectional view of an adhesive structure ofa part of FIG. 30.

FIG. 33 is an illustration of a variation of the adhesive structure inFIG. 32.

FIG. 34 is a cross-sectional view of another variation of the adhesivestructure in FIG. 32.

FIG. 35 is a cross-sectional view of the imaging apparatus according toan embodiment of the present disclosure.

FIG. 36 is a block diagram of a hardware configuration of the imagingapparatus.

FIG. 37 is a rear view of a base frame for describing a first variationof the positioning mechanism according to an embodiment of the presentdisclosure.

FIG. 38 is a perspective view of the base frame for describing the firstvariation of the positioning mechanism according to an embodiment of thepresent disclosure.

FIG. 39 is a rear view of a base frame for describing a second variationof the positioning mechanism according to an embodiment of the presentdisclosure.

FIG. 40 is a perspective view of the base frame for describing thesecond variation of the positioning mechanism according to an embodimentof the present disclosure.

FIG. 41 is a rear view of a base frame for describing a third variationof the positioning mechanism according to an embodiment of the presentdisclosure.

FIG. 42 is a perspective view of the base frame for describing the thirdvariation of the positioning mechanism according to an embodiment of thepresent disclosure.

FIG. 43 is a rear view of a base frame for describing a fourth variationof the positioning mechanism according to an embodiment of the presentdisclosure.

FIG. 44 is a perspective view of the base frame for describing thefourth variation of the positioning mechanism according to an embodimentof the present disclosure.

The accompanying drawings are intended to depict exemplary embodimentsof the present disclosure and should not be interpreted to limit thescope thereof. The accompanying drawings are not to be considered asdrawn to scale unless explicitly noted.

DETAILED DESCRIPTION

In describing embodiments illustrated in the drawings, specificterminology is employed for the sake of clarity. However, the disclosureof this patent specification is not intended to be limited to thespecific terminology so selected and it is to be understood that eachspecific element includes all technical equivalents that have the samefunction, operate in a similar manner, and achieve similar results.

Although the embodiments are described with technical limitations withreference to the attached drawings, such description is not intended tolimit the scope of the disclosure and all of the components or elementsdescribed in the embodiments of this disclosure are not necessarilyindispensable.

The present disclosure is not limited to the following embodiments, andthe constituent elements of the embodiments includes those which can beeasily conceived by those skilled in the art, substantially the sameones, and those in the following embodiments include those which can beeasily conceived by those skilled in the art, substantially the same,and within equivalent ranges. Furthermore, various omissions,substitutions, changes and combinations of constituent elements can bemade without departing from the gist of the following embodiments.

An optical system and an imaging apparatus according to embodiments ofthe present disclosure are described with reference to the drawings. Theimaging apparatus according to the embodiments of the present disclosureincludes a composite lens barrel 10 (FIGS. 4 to 7) incorporating animaging system 1 (an optical system in FIGS. 1 to 3), and is configuredby attaching, for example, an exterior member to the composite lensbarrel 10. The composite lens barrel 10 is formed by symmetricallycombining a lens barrel 11A and a lens barrel 11B each has the samestructure. First, the outline of the imaging system 1 is brieflydescribed, and then the composite lens barrel 10 is described. Asillustrated in FIG. 3, front-to-back direction is parallel to theoptical axis of the front lens of the optical axis between the firstlens and the third lens of a front group AF or BF. Right-to-leftdirections is vertical orthogonal to the front-to-back direction. Asillustrated in FIG. 2, the up-to-down directions is parallel to avirtual line between the top and the bottom of a casing 10.

The imaging system 1 includes two wide-angle lens systems (imagingoptical systems) A and B arranged symmetrical to each other and twoimage sensors AI and BI each to form an image captured by thecorresponding wide-angle lens A/B. Each set of the two wide-angle lenssystems A and B and the image sensors AI and BI may have the samespecification. Each of the wide-angle lens systems A and B has an angleof view greater than 180 degrees. The imaging system 1 may be configuredas a spherical imaging system that combines two images formed by theimage sensors AI and BI to obtain an image with a solid angle of 47 csteradian.

The wide-angle lens system A includes a negative front group AF, a firstprism AP1, a variable aperture stop AS, a second prism AP2, a positiverear group AR, and a third prism AP3, which are arranged in that orderfrom the object side to the image side. The wide-angle lens system Bincludes a negative front group BF, a first prism BP1, a variableaperture stop BS, a second prism BP2, a positive rear group BR, and athird prism BP3, which are arranged in that order from the object sideto the image side. The front group AF/BF is capable of capturing lightrays with wide angles of view of 180 degrees or more, and the rear groupAR/BR is capable of correcting aberrations of an image formed by thelens system A/B. The variable aperture stop AS is illustrated in FIG. 2.

The front group AF diverges light rays of an object that have enteredthe front group AF from the front side (the front group AF side asillustrated in FIG. 1) while causing the diverging light rays to travelbackward (to the front group BF side as illustrated in FIG. 1). Thefirst prism AP1 reflects the light rays traveling from the front groupAF to the left by 90 degrees. The variable aperture stop AS adjusts theamount (amount of light) of transmission of the light reflected by thefirst prism APT The second prism AP2 reflects the light, whose amounthas been adjusted by the variable aperture stop AS, downward by 90degrees. The rear group AR converges the light rays reflected by thesecond prism AP2 while causing the converging light rays to traveldownward. The third prism AP3 reflects the light rays traveling from therear group AR to the right by 90 degrees, and the reflected light raysforms an image on an imaging plane of the image sensor AI. Each of thefront group AF and the rear group AR includes a plurality of lenses.

The front lens group BF diverges light from an object that has enteredthe front group BF from the back side (the front group BF side asillustrated in FIG. 1) while causing the diverging light to travelforward (to the front group AF side as illustrated in FIG. 1). The firstprism BP1 reflects the light traveling from the front group BF to theright (as illustrated in FIG. 2) by 90 degrees. The second prism BP2reflects the light whose amount has been adjusted by the variableaperture stop BS, downward by 90 degrees. The rear group BR convergesthe light reflected by the second prism BP2 while causing the converginglight rays to travel downward. The third prism BP3 reflects the lighttraveling from the rear group BR to the right by 90 degrees, and thereflected light forms an image on an imaging plane of the image sensorBI. Each of the negative front group BF and the positive rear group BRincludes a plurality of lenses.

The slanted surface of the first prism AP1 and the slanted surface ofthe first prism BP1 are in close contact with each other so that thefirst prism AP1 and the first prism BP1 face directions opposite to eachother. In the wide-angle lens system A, the imaging plane of the imagesensor AI faces the left. In the wide-angle lens system B, the imagingplane of the image sensor BI faces the right. The back faces (theopposite plane of each imaging plane) of image sensors AI and BI face inopposite directions.

In each of the wide angle lens system A and the wide angle lens systemB, the optical axes of the front groups AF and BF are defined as theoptical axis X1 (optical axis of incident light). The optical axis ofthe optical path from the reflecting surface of the first prism AP1/BP1to the reflecting surface of the second prism AP2/BP2 is defined as theoptical axis X2. The optical axes of the rear groups AR and BR aredefined as the optical axis X3. The optical axis of the optical pathfrom the reflecting surface of the third prism AP3/BP3 to the imagesensor AI/BI is defined as the optical axis X4. The wide-angle lenssystem A and the wide-angle lens system B are arranged such that theoptical axes X1 are coaxially positioned and oriented in thefront-to-back direction. Further, the front group AF and the front groupBF are arranged to be symmetrical about a predetermined plane (a virtualplane between opposed lenses (the front lenses AF and BF of thewide-angle lens systems A and B)) perpendicular to the optical axis X1along the front-to-back direction.

The optical axes X2, X3 and X4 of the wide-angle lens system A and theoptical axes X2, X3, and X4 of the wide-angle lens system B are locatedwithin the plane between opposed lenses. More specifically, the opticalaxis X2 of the wide-angle lens system A and the optical axis X2 of thewide-angle lens system B are coaxially positioned and oriented in theright-to-left direction. Further, the optical axis X4 of the wide-anglelens system A and the optical axis X4 are coaxially positioned andoriented in the right-to-left direction. Further, the optical axis X3 ofthe rear group AR and the optical axis X3 of the rear group BR arespaced apart in the right-to-left direction in parallel to each other.

As described above, by bending the optical path in different directionsmultiple times within the plane between opposed lenses of the wide-anglelens systems A and B, a long optical path length of the wide-angle lenssystems A and B can be obtained. Further, such a configuration canreduce the distance (the distance between maximum angle-of-view points)between the positions at which the light rays forming a maximum angle ofview enter the lenses closest to the object side (the first lenses L1 ofthe front groups AF and BF) in the wide-angle lens systems A and B. Thedistance between maximum angle-of-view points is illustrated in FIG. 1.As a result, the image sensors AI and BI can be increased in size andthe imaging system 1 can be reduced in size. Further, the disparity thatcorresponds to an overlapping area of two images to be joined bycalibration is reduced, thus obtaining high-quality images.

The composite lens barrel 10 is configured by combining a lens barrel11A supporting the wide-angle lens system A and the image sensor AI, andthe lens barrel 11B supporting the wide-angle lens system B and theimage sensor BI. The lens barrel 11A and the lens barrel 11B have thesame shape (structure) and are symmetrical along the front-to-backdirection to be combinable. With reference to the figures following FIG.4, the lens barrels 11A and 11B are described in detail. Identicalconstituent elements of the lens barrel 11A and the lens barrel 11B aredenoted by the same reference numerals. In each of the lens barrels 11Aand 11B, the object side is the front side, and the opposite side of theobject side is the back side of the front-to-back direction along theoptical axis X1 (of the imaging system 1). The front (object side) ofthe lens barrel 11A faces the front side and the back of the lens barrel11A faces the back side of the front-to-back direction of the imagingsystem 1. The front (object side) of the lens barrel 11B faces the backside and the back of the lens barrel 11B faces the front side of thefront-to-back direction of the imaging system 1.

Each of the lens barrel 11A and the lens barrel 11B according to theembodiments of the present disclosure is an imaging unit that includesan image-forming optical system (wide-angle lens system A/B) and imagesensor (AI/BI) and is capable of independently capturing an image of anobject. In each of the lens barrels 11A and 11B, the image-formingoptical system (wide-angle lens system A/B) and the members (forexample, a base frame 12, a front group frame 13 (an adhesive fixingmember), a rear group frame 14, a third prism frame 15 to be describedbelow) directly or indirectly supporting (holding) the image-formingoptical system constitute the optical system.

Each of the lens barrels 11A and 11B has a base frame 12, a front groupframe 13, a rear group frame 14, a third prism frame 15, and an imagesensor unit 16. Each of the base frame 12, the front group frame 13, therear group frame 14, and the third prism frame 15 is formed as a moldedproduct made of, for example, plastic.

In the lens barrel 11A, the base frame 12 supports the first prism AP1,the variable aperture stop AS, and the second prism AP2. The front groupframe 13 holds the front group AF. The rear group frame 14 holds therear group AR. The third prism frame 15 holds the third prism AP3. Theimage sensor unit 16 is formed by combining, for example, the imagesensor AI and the substrate 17.

In the lens barrel 11B, the base frame 12 supports the first prism BP1,the variable aperture stop BS, and the second prism BP2. The front groupframe 13 holds the front group BF. The rear group frame 14 holds therear group BR. The third prism frame 15 holds the third prism BP3. Theimage sensor unit 16 is formed by combining, for example, the imagesensor BI and the substrate 17.

As illustrated in FIGS. 15 to 19, the base frame 12 includes a frontwall 20, an upper wall 21 positioned at the upper portion of the frontwall 20, and side walls 22 and 23 respectively positioned at the leftand right edges of the front wall 20. The corner wall 24 is providednear the boundary of the upper wall 21 and the side wall 22 and thecorner wall 25 is provided near the boundary of the upper wall 21 andthe side wall 23.

The front wall 20 has a front opening 20 a penetrating the front wall 20in the front-to-back direction and substantially faces an object. Theoptical axis X1 passes through substantially the center of the frontopening 20 a. As illustrated in FIG. 15, the front wall 20 further has aplurality of front group frame contacts 26 (three in the presentembodiment) positioned around the front opening 20 a on the front sideof the front wall 20. Each of the front group frame contacts 26 is aprotrusion provided with a plane perpendicular to the optical axis X1,protruding forward in the front-to-back direction.

The front wall 20 further has a plurality of bonding holes 27 (four inthe present embodiment) around the front opening 20 a. Each of thebonding holes 27 is an elongated hole whose long direction is orientedin the circumferential direction around the optical axis X1, penetratingthe front wall 20 in the front-to-back direction. A joint face 28 facingforward is formed around each of the bonding holes 27. A plurality ofbonding recessed portions is formed on the outer edge of the frontopening 20 a.

As illustrated in FIGS. 1 and 3, each of the front group AF and thefront group BF includes a first lens L1, a second lens L3, and a thirdlens L3. As illustrated in FIGS. 30 and 31, the front group frame 13includes an annular first lens holder 13 a that supports (holds) thefirst lens L1, an annular second lens holder 13 b that holds the secondlens L2, and an annular third lens holder 13 c that holds the third lensL3.

As illustrated in FIGS. 30 and 31, the first lens L1 held by the firstlens holder 13 a of the front group frame 13 is a negative meniscus lenshaving a convex surface facing the object side. An annular plane L1 a isformed on the periphery of a concave surface, which outputs light, ofthe first lens L1 and is perpendicular to the optical axis X1. The firstlens holder 13 a has an annular lens supporting surface 30 on the frontside, to support the plane L1 a. The lens supporting surface 30includes, on the back, a joint face 31 facing the front face (includingthe joint face 28) of the front wall 20 of the base frame 12 and aplurality of contacts 32 (three in the present embodiment) positionedaround the periphery of the joint face 31. Each of the contacts 32 is aprotrusion provided with a plane perpendicular to the optical axis X1,protruding backward from the joint face 31 in the front-to-backdirection. Each of the contacts 32 is positioned to face the front groupframe contact 26 of the base frame 12.

A plurality of bonding holes 33 (four in the present embodiment) isfurther formed in the first lens holder 13 a of the front group frame13. Each of the bonding holes 33 is an elongated hole whose longdirection is oriented in the circumferential direction around theoptical axis X1, penetrating the first lens holder 3 a in thefront-to-back direction. The lens supporting surface 30 side of thebonding holes 33 is covered with the plane L1 a of the first lens L1,and the joint face 31 side of the bonding holes 33 is open.

As illustrated in FIGS. 30 to 32, each contact 32 of the front groupframe 13 comes into contact with each front group frame contact 26 ofthe base frame 12 so that the front group frame 13 is positionedrelative to the base frame 12 in the front-to-back direction. The secondlens holder 13 b and the third lens holder 13 c have a smaller diameterthan the first lens holder 13 a does and are configured to enter thefront opening 20 a. In such a state, there is space in the radialdirection about the optical axis X1 between the front opening 20 a andthe second and third lens holders 13 b and 13 c, which enables theposition of the front group frame 13 to be adjustable (opticaladjustment) relative to the base frame 12 along the directionperpendicular to the optical axis X1. After positional adjustment, thefront group frame 13 is bonded by adhesive to the base frame 12. Thefollowing describes an adhesive structure.

As illustrated in FIG. 29, when the contact 32 of the front group frame13 is in contact with the front group frame contact 26 of the base frame12 and viewed from the back side of the front group frame 13, fourbonding holes 27 and bonding holes 33 are communicated with each other.Further, the back surface of the third lens holder 13 c of the frontgroup frame 13 is exposed through the bonding recessed portion 29. Thebonding holes 27, the bonding holes 33, and the bonding recessedportions 29 are filled with adhesive, and the adhesive is cured. Thus,the front group frame 13 is fixed to the base frame 12. For example,when the front group frame 13 is positioned after the positionaladjustment, the bonding recessed portion 29 is filled with anultraviolet curing adhesive that is then irradiated with ultravioletrays to temporarily fix the front group frame 13 thereto. Subsequently,the bonding holes 27 and the bonding holes 33 are filled with adhesivehaving a strong adhesive force, and the final fixation is performed.

The sectional structure in the vicinity of the bonding hole 27 and thebonding hole 33 is enlarged and illustrated in FIG. 32. The bonding hole27 has a narrow portion (first portion) 27 a, a wide portion (secondportion) 27 b, and a width-gradual change portion (third portion) 27 c.The first portion 27 a opens toward the front side (the joint face 28side). The second portion 27 b opens toward the back side. The thirdportion 27 c is disposed between the first portion 27 a and the secondportion 27 b. The second portion 27 b has longer lengths in the radialdirection and circumferential direction with the optical axis X1 as thecenter than the first portion 27 a does. That is, the second portion 27b has a larger cross-sectional area than the first portion 27 a does.The third portion 27 c has lengths in the radial direction andcircumferential direction that gradually increase in a direction fromthe first portion 27 a to the second portion 27 b. That is, the thirdportion 27 c has a cross-sectional area that gradually increase in adirection from the first portion 27 a to the second portion 27 b. Withsuch a configuration, when the bonding hole 27 is viewed in crosssection along the direction of the optical axis X1 as illustrated inFIG. 32, the inner surfaces of the first portion 27 a and the secondportion 27 b are parallel to the optical axis X1, whereas the thirdportion 27 c has an inner surface that forms an adhesive fitting face 27d of a tapered shape whose width increases toward the back side.

The bonding hole 33 includes a narrow portion (first portion) 33 a, awide portion (second portion) 33 b, and a width-gradual change portion(third portion) 33 c. The first portion 33 a opens toward the back side(the joint face 31 side). The second portion 33 b opens toward the frontside (the lens supporting surface 30 side). The third portion 33 c isdisposed between the first portion 33 a and the second portion 33 b. Thesecond portion 33 b has longer lengths in the radial direction andcircumferential direction with the optical axis X1 as the center thanthe first portion 33 a does. That is, the second portion 33 b has alarger cross-sectional area than the first portion 33 a does. In thewidth gradually changing portion 33 c, the width in the radial directionand the length in the circumferential direction gradually increase (thesectional area increases) gradually from the narrow portion 33 a to thewide portion 33 b. In such a configuration, when the bonding hole 33 isviewed in cross-section along the direction of the optical axis X1 asillustrated in FIG. 32, the inner surfaces of the first portion 33 a andthe second portion 33 b are parallel to the optical axis X1, whereas thethird portion 33 c has an inner surface that forms an adhesive fittingface 33 d of a tapered shape whose width increases toward the frontside.

Each bonding hole 27 is larger than a corresponding bonding hole 33(communicable along the front-to-back direction). When the bonding hole27 is viewed from the back side, the joint face 31 of the front groupframe 13 is visually recognized around the bonding hole 33 (see FIG.29). More specifically, the first portion 27 a of the bonding hole 27has the same width in the radial direction (the width in the verticaldirection in FIG. 32) around the optical axis X1, as that of the secondportion 33 b of the bonding hole 33. The first portion 33 a has thesmallest width, and the second width 27 b has the largest width amongthe portions of the bonding hole 27 and the bonding hole 33. Further,each bonding hole 27 is longer in the circumferential direction aroundthe optical axis X1 than each corresponding bonding hole 33 (see FIG.29). With such a difference in size between the bonding hole 27 and thebonding hole 33, the bonding hole 33 of the front group frame 13 iscommunicable with the bonding hole 27 of the base frame 12 without beingblocked when the position of the front group frame 13 is adjustedrelative to the base frame 12 within a predetermined range. Accordingly,adhesive can be smoothly injected (applied) from the bonding hole 27side to the bonding hole 33 side. Further, in the configuration thatbonds the bonding hole 27 and the bonding hole 33 (the bonding target isthe bonding hole 27 and the bonding hole 33), even if the amount ofadjustment is greater than a predetermined value and a part of the firstportion 33 a exceeds the range of the first portion 27 a, the adhesivecan be applied from the bonding hole 27 side to the bonding hole 33.With such a configuration, the amount of adjustment is more flexiblethan a configuration that inserts a projection into a hole to bond theprojection and the hole does. As illustrated in FIG. 32, with thecontact 32 in contact with the front frame contact 26, there is a slightgap between the joint face 28 and the joint face 31 along thefront-to-back direction. The bonding hole 27 and the bonding hole 33 arecommunicated with the gap.

As indicated by arrow Tin FIG. 32, the adhesive injected from the secondportion 27 b side of the bonding hole 27 flows to the bonding hole 33through the third portion 27 c and the first portion 27 a. A thin sheetis sandwiched between the lens supporting surface 30 and the plane L1 aof the first lens L1. This sheet prevents the adhesive from leaking fromthe bonding hole 33 so that the bonding hole 33 and the bonding hole 27are filled with the adhesive. Depending on the viscosity of theadhesive, a part of the adhesive spreads to the gap between the jointface 28 and the joint face 31. The adhesive filling in the bonding hole33 and the bonding hole 27 is hardened to a solid state from the fluidstate as time lapses or with application of energy (for example,heating), so that the base frame 12 and the front group frame 13 arefixed to each other. The adhesive U injected into the bonding hole 27and bonding hole 33 and cured is virtually indicated by a two-dot chainline in FIG. 32.

The adhesive U is injected into both the bonding hole 27 and the bondinghole 33, which provides a strong fixing force. With such a strong fixingforce, when a load is applied in the radial direction around the opticalaxis X1 or in the circumferential direction around the optical axis X1,relative movement between the base frame 12 and the front group frame 13can be reliably prevented.

Further, when a load is applied in the front-to-back direction so as toseparate the joint face 28 of the base frame 12 from the joint face 31of the front group frame 13, the cured adhesive U fit into both thebonding hole 27 and bonding hole 33 prevents the separation of the jointface 28 of the base frame 12 from the joint face 31 of the front groupframe 13. More specifically, the bonding hole 27 and the bonding hole 33are formed such that the opening widths of the joint face 28 side andthe joint face 31 side of the bonding hole 27 and the bonding hole 33(the widths of the first portion 27 a and the first portion 33 a) facingeach other are small. Further, a cross-sectional area is substantiallyformed such that the tip portions of two wedges facing in oppositedirections are joined. Accordingly, the adhesive U injected in thebonding hole 27 and the bonding hole 33 also has the same shape as thatof the cross-sectional area.

In such a configuration, when a load is applied to the front group frame13 in a direction away from the base frame 12 (to the front side), aload in the same direction acts on the cured adhesive U through theadhesive fitting face 33 d. Accordingly, the adhesive U acts like awedge against the adhesive fitting face 27 d that faces the oppositedirection (the back side) of the direction in which the adhesive fittingface 33 d faces. This action prevents the front group frame 13 fromseparating from the base frame 12. Same as in the case of the oppositedirection, when a load is applied to the base frame 12 in a directionaway from the front group frame 13 (to the back side), a load in thesame direction acts on the cured adhesive U through the adhesive fittingface 27 d. Accordingly, the adhesive U acts like a wedge against theadhesive fitting face 33 d that faces the opposite direction (the frontside) of the direction in which the adhesive fitting face 27 d faces.This action prevents the front group frame 13 from separating from thebase frame 12.

The adhesive structure according to an embodiment of the presentdisclosure exhibits the wedge effect using the adhesive U, the adhesivefitting face 27 d, and the adhesive fitting face 33 d of the bondinghole 27 and the bonding hole 33 that are tilted in opposite directionsalong the front-to-back direction. Hence, such a configuration increasesthe strength of adhesion between the base frame 12 and the front groupframe 13 as compared to a configuration that relies on the adhesive Ufixed to the first portions 27 a and 33 a and the second portions 27 band 33 b whose inner surfaces extend along the front-to-back direction.With such a configuration that provides a superior adhesive strengthbetween each bonding hole 27 and each corresponding bonding hole 33, thenumber of bonding locations and a bonding area can be reduced so as toprovide the fixation of the components. Thus, the lens barrel 1A and thelens barrel 11B are disposed compactly and a latitude for designing thelens barrels is increased. Particularly in the composite lens barrel 10according to the embodiments of the present disclosure, the space of thefront group frame 13 is reduced more successfully and fixed withadhesive more firmly as the first prisms AP1 and BP1 and the secondprisms AP2 and BP2 are densely packed onto the back side of the baseframe 12 to be described later.

The adhesive structure used for bonding the base frame 12 and the frontgroup frame 13 is not limited to the above-described structure. FIGS. 33and 34 are illustrations of variations of the adhesive structure. FIG.33 is an illustration of a configuration in which the bonding hole 127of the base frame 12 and the bonding hole 133 of the front group frame13 have the adhesive fitting face 27 e and the adhesive fitting face 33e of tapered shapes as a whole whose widths decrease in directions tothe joint face 28 and the joint face 31, respectively. FIG. 34 is anillustration of a configuration in which the bonding hole 227 of thebase frame 12 and the bonding hole 233 of the front group frame 13 has aplane adhesive fitting face 27 f and a plane adhesive fitting face 33 fperpendicular to the optical axis X1, respectively, instead of theabove-described adhesive fitting face 27 d and adhesive fitting face 33d. In these configurations of FIGS. 33 and 34, the adhesive fitting face27 e and the adhesive fitting face 33 e face in opposite directions andform a pair of fitting faces to fit the adhesive U, and the adhesivefitting face 27 f and the adhesive fitting face 33 f face in oppositedirections and form a pair of fitting faces to fit the adhesive U.Accordingly, these configurations exhibit the same advantageous effectas that of the above-described configuration.

Alternatively, a combination of the bonding hole 27 (FIG. 32), thebonding hole 127 (FIG. 33), or the bonding hole 227 (FIG. 34), which isdisposed on the base frame 12 side, and the bonding hole 33 (FIG. 32),the bonding hole 133 (FIG. 33), or the bonding hole 233 (FIG. 34), whichare disposed on the front group frame 13 side, may be changed asappropriate so as to obtain a pair of fitting faces that form anasymmetrical shape in the front-to-back direction.

Any of the bonding holes 27, 127, and 227 of the base frame 12 and thebonding holes 33, 133, and 233 of the front group frame 13 has a shapeeasily manufactured by a mold that releases in the front-rear direction.Accordingly, the base frame 12 and the front group frame 13 can beeasily obtained without an increase in manufacturing cost.

The following further describes the configuration of the base frame 12.As illustrated in FIGS. 16 to 19, the upper wall 21 extends from theupper edge of the front wall to the back side of the composite lensbarrel 10, and has a top portion 21 a (top portions of the lens barrels11A and 11B and a pair of side portions 21 b and 21 c that extend fromright and left edges of the top portion 21 a to the down side of thecomposite lens barrel 10. The upper wall 21 forms a U shape defined bythe top portion 21 a in the upper side and the side portions 21 b and 21c in the right and left sides of the upper wall 21 in which the downside is open.

The side wall 23 and the side wall 22 are disposed below the upper wall21 and extend from the right and left side edges to the back side of thecomposite lens barrel 10, respectively. Each of the area that rangesfrom the front wall 20 to the side wall 22 and the area that ranges fromthe front wall 20 to the side wall 23 forms a curve shape that outlinesthe rear group frame 14 to be described later.

Each of the corner wall 24 and the corner wall 25 faces oppositedirections in substantially the front-to-back direction, and isdisplaced to the back side relative to the front wall 20. The cornerwall 24 projects laterally from the side portion 21 b of the upper wall21, and the lower end of the corner wall 24 is connected to the upperportion of the side wall 22. The corner wall 25 projects laterally fromthe side portion 21 c of the upper wall 21, and the lower end of thecorner wall 25 is connected to the upper portion of the side wall 23.The corner wall 24 and the corner wall 25 are connected to a pluralityof walls that extend in different directions, which increases thesupporting strength so as to prevent deformation of the corner walls 24and 25.

The base frame 12 further includes a first prism holder 35 (reflectiveoptical element holder) and a second prism holder 36 (reflective opticalelement holder) on the back surface of the front wall 20. The firstprism holder 35 serves to hold the first prism AP1 or the first prismBP1 on the back of the front opening 20 a. The second prism holder 36serves to hold the second prism AP2 or the second prism BP2.

The first prism holder 35 has an upper wall 35 a on the upper edge sideof the front opening 20 a and a lower wall 35 b on the lower edge sideof the front opening 20 a. On one end of the upper wall 35 a in theright-to-left direction, a vertical wall 35 c is formed to projectdownward. On the other end of the lower wall 35 b in the right-to-leftdirection, a vertical wall 35 d is formed to project upward.

The first prisms AP1 and BP1 are disposed between the upper wall 35 a,the lower wall 35 b, the vertical wall 35 c, and the vertical wall 35 d.There is a clearance between each of the walls 35 a, 35 b, 35 c, 35 dand the first prism AP1/BP1, and the first prism AP1/BP1 is positionedusing the positioning tool before bonding the first prism AP1/BP1 to thefirst prism holder 35 with adhesive.

As described above, in the composite lens barrel 10 completelyassembled, the slanted surfaces of the first prism AP1 and the firstprism BP1 are in close contact with each other, facing oppositedirections. With such an arrangement, the first prism holder 35 isformed to leave uncovered the back sides of the slanted surfaces of thefirst prism AP1 and the first prism BP1 so that the back sides of theslanted surfaces of the first prism AP1 and the first prism BP1 areexposed to the outside of the composite lens barrel 10.

The second prism holder 36 is disposed below the side portion 21 b ofthe upper wall 21 and the corner wall 24, and includes a support seat 36a facing the back side of the composite lens barrel 10 and a supportwall 36 b that projects from the support seat 36 a to the back side ofthe composite lens barrel 10. The side surfaces of the second prism AP2and BP2 contact the support seat 36 a. The slanted surfaces of thesecond prism AP2 and BP2 contact the support wall 36 b. The secondprisms AP2 and BP2 are positioned in the direction of slant using thepositioning tool. Then, the positioned second prisms AP2 and BP2 arebonded (fixed) to the second prism holder 36 with adhesive.

FIG. 13 is an illustration of the rear group frame 14 alone without thebase frame 12 attached to. As illustrated in FIGS. 9, 13, and 14, therear group frame 14 has a cylindrical portion 14 a having asubstantially cylindrical shape with the optical axis X3 extending inthe vertical direction as the center. Further, a plurality of lensesconstituting the rear group AR or BR is fixedly held within thecylindrical portion 14 a. The rear group frame 14 further includes aprism cover 14 b on the upper portion of the cylindrical portion 14 a. Asupport tab 14 c projects laterally from the cylindrical portion 14 a,and a support tab 14 d projects upward from the prism cover 14 b. Ajoining flange 14 e is formed at the lower end of the cylindricalportion 14 a.

As illustrated in FIGS. 16 to 19, on the back side of the base frame 12,a rear group frame holder 37 (lens positioner) is formed below thecorner wall 24 and the second prism holder 36. The rear group frameholder 37 is a concave portion surrounded by the front wall and the sidewall 22 and has a shape that enables substantially half (portionpositioned on the front side) of the cylindrical portion 14 a of therear group frame 14 to be accommodated within the rear group frameholder 37. The prism cover 14 b covers a part of the second prisms AP2and BP2 held by the second prism holder 36 of the base frame 12 with thecylindrical portion 14 a accommodated in the rear group frame holder 37.

A support seat 38 (the lens positioner) is formed on the side of therear group frame holder 37 (below the lower wall 35 b of the first prismholder 35), and a support seat 39 (the lens positioner) is formed abovethe second prism holder 36. Each of the support seat 38 and the supportseat 39 has an annular plane perpendicular to the optical axis X1, and ascrew hole is formed in the center of the annular plane. With thecylindrical portion 14 a of the rear group frame 14 accommodated in therear group frame holder 37, the support tab 14 c contacts the supportseat 38, and the support tab 14 d contacts the support seat 39.Through-holes are formed respectively in the support tab 14 c and thesupport tab 14 d. The fixing screw 40 is screwed into the screw hole ofthe support seat 38 through the through-hole of the support tab 14 c,and the fixing screw 41 is screwed into the screw hole of the supportseat 39 through the through-hole of the support tab 14 d. By tighteningthe fixing screw 40 and the fixing screw 41, the rear group frame 14 isfixed to the base frame 12 with the position of the rear group frame 14determined (see FIG. 14).

On the back side of the base frame 12, a rear group frame accommodatingsection 42 (a lens accommodating section) is formed below the cornerwall 25. The rear group frame accommodating section 42 is a recessedportion surrounded by the front wall 20 and the side wall 23 and has ashape that enables substantially half (portion positioned on the backside) of the cylindrical portion 14 a of the rear group frame 14 to beaccommodated within the rear group frame accommodating section 42. Priorto combining the lens barrel 11A and the lens barrel 11B, the rear groupframe accommodating section 42 is an empty space (see FIGS. 9 and 14).When the lens barrel 11A and the lens barrel 11B are combined, the reargroup frame holder 37 of one base frame 12 and the rear group frameaccommodating section 42 of the other base frame 12 face each other inthe front-to-back direction, so as to form space to accommodate thecylindrical 14 a of the rear group frame 14 inside the combination ofthe lens barrel 11A and the lens barrel 11B.

The third prism frame 15 includes a prism support wall 15 a thatsupports the slanted surfaces and side surfaces of the third prisms AP3and BP3. Each of the third prisms AP3 and BP3 is bonded (fixed) to thethird prism frame 15 with adhesive. On the upper portion of the thirdprism frame 15, a joining flange 15 b is provided. The joining flange 15b can be fitted into the joining flange 14 e of the rear group frame 14from below. With the joining flange 15 b fitted to the joining flange 14e, the third prism frame 15 is positioned and fixed to the rear groupframe 14 with adhesive.

The image sensor unit 16 is provided with a pair of fitting pieces 43 atthe edge in the front-to-back direction. The pair of fitting pieces 43are fitted into the recesses formed in the prism support wall 15 a ofthe third prism frame 15, which positions the image sensor unit 16relative to the third prism frame 15. The image sensor unit 16 is fixedto the third prism frame 15 with adhesion. With such a state, theimaging planes of the imaging sensors AI and BI face in a directionperpendicular to the optical axis X4. Further, the imaging plane of theimage sensor AI faces the exit surface of the third prism AP3, and theimaging plane of the image sensor BI faces the exit surface of the prismBP3.

The image sensor unit 16 includes a substrate 17 having image sensors AIand BI on one side. The substrate 17 is substantially rectangular. Withthe image sensor unit 16 bonded to the third prism frame 15, the longdirection of the substrate 17 is along the up-and-down directions, andthe lateral direction of the substrate 17 is along the front-to-backdirection of the imaging apparatus 80. Further, the direction ofthickness of the substrate 17 is along right-to-left direction. In thevicinity of the lower end of the substrate 17, a connector 17 a to beconnected to the control circuit of the imaging apparatus 80 isdisposed. The connector 17 a is disposed on the side of the substrate 17on which the image sensors AI and BI are provided.

By combining the above-described constituent elements, each of the lensbarrel 11A and the lens barrel 11B is completely assembled. FIGS. 9 to12 are illustrations of the lens barrel 11A and the lens barrel 11B,which are separated from each other. FIGS. 13 and 14 are illustrationsof one of the lens barrel 11A and the lens barrel 11B. As can be seenfrom these drawings, the lens barrel 11A and the lens barrel 11B havethe same structures.

As illustrated in FIG. 10, each of the lens barrel 11A and the lensbarrel 11B has a size in the front-to-back direction accommodated withinthe width in the lateral direction (the front-to-back direction) of thesubstrate 17, except for a portion where each of the front groups AF andBF and a part of the front group frame 13 are exposed to the outside ofthe imaging apparatus 80. Each of the wide-angle lens system A and B isconfigured to be a folded optical system in which the optical path isbent multiple times using a plurality of prisms (the light is reflected(redirected) by a prism multiples times (a plurality of prisms aredisposed to reflect the light multiple times)) within a plane (planebetween the lenses closest to the object side in the wide-angle lenssystems A and B) perpendicular to the optical axis X1. Thisconfiguration enables the lens barrel 11A and the lens barrel 11B to bethin in the front-to-back direction.

The lens barrel 11A and the lens barrel 11B having the same structureare combined to be together and opposed to each other along thefront-to-back direction (see FIGS. 9 and 12), which provides thecomposite lens barrel 10 in a complete state as illustrated in FIGS. 4to 8. As illustrated in FIGS. 9 to 12, the lens barrel 11A and the lensbarrel 11B have a structure in which the protrusions and recesses of thelens barrel 11A and the lens barrel 11B are combined by bringing thelens barrels 11A and 11B together. This configuration enables the lensbarrel 11A and the lens barrel 11B to be coupled to each othercompactly.

In FIG. 5, a virtual plane Q1 and a virtual plane Q2 are indicated. Thevirtual plane Q1 includes the optical axis X1 and extends along theup-to-down direction. The virtual plane Q2 is perpendicular to thevirtual plane Q1 and passes through the lower end of the base frame 12.In the lens barrel 11A, the optical path from the second prism AP2 tothe image sensor AI after being bent by the first prism AP1 passesthrough the left area of the virtual plane Q1. In the lens barrel 11B,the optical path from the second prism BP2 to the image sensor BI afterbeing bent by the first prism BP1 passes through the right area of thevirtual plane Q1. As illustrated in FIGS. 11 and 12, on the left side ofthe virtual plane Q1, the constituent elements of the lens barrel 11Aproject beyond the base frame 12 to the back side of the imagingapparatus 80, whereas the constituent elements of the lens barrel 11Bdoes not project beyond the base frame 12 to the front side of theimaging apparatus 80. Similarly, on the right side of the virtual planeQ1, the constituent elements of the lens barrel 11B project beyond thebase frame 12 to the front side of the imaging apparatus 80, whereas theconstituent elements of the lens barrel 11A do not project beyond thebase frame 12 to the back side of the imaging apparatus 80. Thus, whenthe lens barrel 11A and the lens barrel 11B are combined, the rear groupframes 14, the third prism frames 15, and the image sensor units 16 onthe lens barrel 11A side and the lens barrel 11B side are arranged sideby side symmetrically without interfering with each other.

Further, in the wide-angle lens systems A and B, light beams from theobject, which have been reflected by the first prisms AP1 and BP1 to theleft and right, respectively, are reflected by the third prisms AP3 andBP3 to travel in a direction to the virtual plane Q1 and reach the imagesensors AI and BI, respectively. For this reason, the image sensor unit16 on the lens barrel 11A side is close to the image sensor unit 16 onthe lens barrel 11B side along right-to-left direction. Particularly,the substrate 17 on the lens barrel 11A side is close to the substrate17 on the lens barrel 11B side across the virtual plane Q1. In thecentral portion of each of the lens barrels 11A and 11B alongright-to-left direction, the first prism AP1/BP1 is disposed above thevirtual plane Q2, and the two image sensor units 16 are arranged withthe back surfaces opposed to each other below the virtual plane Q2. Thesubstrates 17 on the lens barrel 11A side and the lens barrel 11B sidehas a planar shape substantially parallel to the virtual plane Q1.Further, there is a clearance between the substrates 17 on the lensbarrel 11A side and the lens barrel 11B side in the right-to-leftdirection. Such a configuration prevents these substrates 17 frominterfering with each other when the lens barrel 11A is brought close tothe lens barrel 11B.

Since the first prism AP1 and the first prism BP1 are arranged such thatthe slanted surfaces of the first prism AP1 and the first prism BP1 arein close contact with each other, the thickness of the composite lensbarrel 10 in the front-to-back direction that is substantially occupiedby the two prisms AP1 and BP1 merely corresponds to the space for oneprism although the two prisms AP1 and BP1 are arranged side by side inthe front-to-back direction (see FIG. 3). Further, the image sensor unit16 of the lens barrel 11A and the image sensor unit 16 of the lensbarrel 11B are substantially at the same position in the front-to-backdirection and are arranged side by side in the right-to-left direction.Accordingly, with a space in the front-to-back direction of thecomposite lens barrel 10 sufficient to accommodate the width of onesubstrate 17 in the lateral direction, the two image sensor units 16 areable to be accommodated below the first prisms AP1 and BP1 in thecomposite lens barrel 10. With such a configuration, the thickness ofthe composite lens barrel 10 in the front-to-back direction can bereduced for the central portion of the composite lens barrel 10 in theright-to-left direction in which the constituent elements (the firstprisms AP1 and BP1 and the image sensor units 16) of the lens barrels11A and 11B overlap and for the vicinity of the ends of the compositelens barrel 10 in the right-to-left direction in each of which theconstituent elements (the rear group frame 14 and the third prism frame15) of one of the lens barrels 11A and 11B are disposed.

As described above, the constituent elements of the lens barrels 11A andthe lens barrel 11B are disposed compactly in the composite lens barrel10 in the front-to-back direction, the right-to-left direction, and theup-to-down direction. Thus, a compact structure is provided whileincluding two lens barrels 11A and 11B.

As described above, the lens barrel 11A and the lens barrel 11B aredisposed symmetrically along the front-to-back direction and broughttogether along the front-to-back direction so as to be combined witheach other. Note that the lens barrel 11A and the lens barrel 11B arecombined with a stable relative position such that the optical systems(the wide-angle lens systems A and B) of the lens barrels 11A and 11Bface in the proper directions. Specifically, the lens barrel 11A and thelens barrel 11B are positioned in the front-front-to-back directionalong the optical axis X1 and positioned in a direction along the planeperpendicular to the optical axis X1 (the up-to-down and right-to-leftdirections). Further, in order to make the imaging system 1 includingthe two optical systems (wide-angle lens systems A and B) work, aftercombining the lens barrel 11A and the lens barrel 11B (morespecifically, after calibration of the imaging system 1 including thewide-angle lens systems A and B), a high bonding strength is needed toprevent a change in the relative positions between the lens barrels 11Aand the lens barrel 11B due to, for example, external force.

A description is given of the structure that positions the lens barrel11A and the lens barrel 11B in the front-to-back direction. On the baseframe 12, a contact surface 50 is disposed on the back surface of thecorner wall 24, and a contact surface 51 is disposed on the back surfaceof the corner wall 25. The contact surface 50 is formed as an endsurface of a cylindrical boss 52 projecting forward and backward beyondthe corner wall 24, and the contact surface 51 is formed as an endsurface of a cylindrical boss 53 projecting forward and backward beyondthe corner wall 25. Both the contact surface 50 and the contact surface51 are annular planes perpendicular to the optical axis X1 and have asymmetrical shape in the front-to-back direction.

In the interior of the boss 52, a screw hole 54 whose long axis line isoriented in the front-to-back direction is formed. The screw hole 54 isopen at the end on the back side at the contact surface 50, and theopposite front end is closed. Inside the boss 53, screw insertion holes55 penetrating in the front-to-back direction are formed.

FIGS. 9 to 12 are illustrations of the lens barrel 11A and the lensbarrel 11B with the contact surface 50 and the contact surface 51 of thelens barrel 11A facing the contact surface 51 and the contact surface 50of the lens barrel 11B, respectively. When the lens barrel 11A and thelens barrel 11B are brought together in the front-to-back direction withthis relative position, the contacts surface 50 of the lens barrels 11Aand 11B come into contact (abut) with and the contacts surface 51 of thelens barrels 11A and 11B, respectively, which determines the relativepositions of the lens barrels 11A and 11B in the front-to-backdirection. With such a contact state, the positional accuracy of thelens barrel 11A and lens barrel 11B of the composite lens barrel 10 inthe front-to-back direction is controlled.

A screw is used to fix the lens barrel 11A to the lens barrel 11B.Specifically, a fixing screw is inserted into the screw insertion hole55 of the lens barrel 11A from the front and screwed into the screw hole54 of the lens barrel 11B. Further, a fixing screw is inserted into thescrew hole 54 of the lens barrel 11B and screwed into the screwinsertion hole 55 of the lens barrel 11B. By tightening the fixingscrews, the lens barrel 11A and the lens barrel 11B are fixed to eachother.

The base frame 12 of each of the lens barrels 11A and 11B holds(supports) a plurality of prisms (the first prism AP1, the first prismBP1, the second prism AP2, and the second prism BP2). Further, the frontgroup frame 13 and the rear group frame 14 are attached to the baseframe 12. That is, all the optical elements are supported by the baseframe 12 as a support reference. Accordingly, as the assembly accuracyof the base frame 12 exerts a particularly great influence on theoptical performance, the base frame 12 is provided with the contactsurfaces 50 and 51 that serve as a relative position reference in thefront-to-back direction of each of the lens barrels 11A and 11B.

The contact surface 50 and the contact surface 51 are disposed at theright and left ends of the base frame 12 along the right-to-leftdirection. The maximum distance between the contact surface 50 and thecontact surface 51 in the right-to-left direction are provided under thedimensional restriction of the base frame 12. With an increase in thedistance between the contact surface 50 and the contact surface 51serving as a position reference, the two base frames 12 effectively areprevented from being tilted, and thus the accuracy of positioning of thelens barrels 11A and 11B is increased. As illustrated in FIG. 14, thecontact surface 50 is disposed in a space on the back of the slantedsurfaces of the second prisms AP2 and BP2. That is, the space isefficiently utilized. The contact surface 50 is disposed above the reargroup frame holder 37 that holds the rear group frame 14. The contactsurface 51 is disposed above the rear group frame accommodating section42 that covers the rear group frame 14 from the back side. With such anarrangement, the contact surfaces 50 and 51 are disposed so as not tooverlap with the positions of the rear groups AR and BR, the firstprisms AP1 and BP1, and the second prisms AP2 and BP2, which are held bythe respective base frames 12 on the back side. Further, the contactsurface 50 and the contact surface 51 are disposed with a wide distancebetween the contact surface 50 and the contact surface 51.

The corner wall 24 includes the contact surface 50, and the corner wall25 includes the contact surface 51. The corner wall 24 and the cornerwall 25 are connected to the plurality of walls facing differentdirections in the vicinity of the upper wall 21 and the side walls 22and 23. Accordingly, the corner wall 24 and the corner wall 25 have aplanar shape and still high rigidity. That is, the contact surface 50and the contact surface 51 have a high surface accuracy, which preventsthe corner walls 24 and 25 from being distorted and allows for highlyaccurate of positioning when the contact surface 50 contacts the contactsurface 51.

Further, as illustrated in FIG. 5, the boss 52 having the contactsurface 50 and the boss 53 having the contact surface 51 are disposedsubstantially symmetrically relative to the optical axis X1 along theright-to-left direction. Such an arrangement provides a positioningaccuracy equal in the front-to-back direction on the right and leftsides of the optical axis X1, and is particularly advantageous inobtaining the positional accuracy of front groups AF and BF and thefirst prisms AP1 and BP1. Further, since the contact surfaces 50 and 51provides high positioning accuracy and stability, the lens barrel 11Aand the lens barrel 11B are combined without interfering with eachother.

For example, when the lens barrel 11A is combined with the lens barrel11B, the cylindrical portion 14 a of the rear group frame 14 of acorresponding lens barrel 11A/11B comes into the rear group frameaccommodating section 42 on the back side of each base frame 12, so thatthe cylindrical portion 14 a (the rear group AR/BR) is positionedbetween the rear group frame holder 37 and the rear group frameaccommodating section 42, which are opposed to each other. At this time,the rear group frame 14 (the rear group frame 14 on the lens barrel 11Aside) that holds the rear group AR is covered from the back side (rearside) by the rear group frame accommodating section 42 provided on thebase frame 12 of the lens barrel 11B. However, the rear group frameaccommodating section 42 on the lens barrel 11B side is not in contactwith the rear group frame 14 on the lens barrel 11A side because thereis a clearance therebetween in the front-to-back direction. Accordingly,the rear group frame 14 of the lens barrel 11A side is maintained (held)at a proper position within the rear group frame holder 37 on the baseframe of the lens barrel 11A. Similarly, the rear group frame 14 (therear group frame 14 on the lens barrel 11B side) that holds the reargroup BR is covered from the back side (front side) by the rear groupframe accommodating section 42 provided on the base frame 12 of the lensbarrel 11A. However, the rear group frame accommodating section 42 onthe lens barrel 11A side is not in contact with the rear group frame 14on the lens barrel 11B side because there is a clearance therebetween inthe front-to-back direction. Accordingly, the rear group frame 14 of thelens barrel 11B side is maintained (held) at a proper position withinthe rear group frame holder 37 on the base frame of the lens barrel 11B.In that manner, the base frames 12 are stably positioned with a highdegree of accuracy using the contact surfaces 50 and 51, and thus eachrear group frame 14 can be accommodated at a proper position of the reargroup frame accommodating section 42 of each base frame 12 without anyinterference.

Each of the contact surface 50 and the contact surface 51 is a planeperpendicular to the optical axis X1, and has a symmetrical shape alongthe front-to-back direction. With such a configuration, when the lensbarrel 11A is brought into contact with the lens barrel 11B along theoptical axis X1 in the front-to-back direction so as to cause thecontact surface 50 to contact the contact surface 51, no excess force isgenerated and a reliable and accurate positioning is made along thefront-to-back direction.

The boss 52 having the contact surface 50 and the boss 53 having thecontact surface 51 are both easily formed by a mold that separates inthe front-to-back direction. Thus, the base frame 12 can be easilymanufactured without an increase in cost.

When the lens barrel 11A is fixed to the lens barrel 11B with thecontact surfaces 50 and 51 contact each other, the upper walls 21, theside walls 22, and the side walls 23 of the base frames 12 are combinedto form the outer wall of the composite lens barrel 10 that continuousin the front-to-back direction. More specifically, on the upper surfaceof the composite lens barrel 10, the edge portions of the upper walls 21(top portion 21 a) of the lens barrel 11A and the lens barrel 11B are incontact with each other. On the left side surface of the composite lensbarrel 10, the edge portion of the side wall 22 of the lens barrel 11Ais in contact with the edge portion of the side wall 23 of the lensbarrel 11B. On the right side surface of the composite lens barrel 10,the edge portion of the side wall 23 of the lens barrel 11A is incontact with the edge portion of the side wall 22 of the lens barrel11B. These edge portions are opposed to each other with a slightclearance therebetween when the contact surfaces 50 and 51 contact eachother, which exerts no influence on the positioning accuracy in thefront-to-back direction by the contact surface 50 contacting the contactsurface 51. A light shielding structure (a light shield: a rib 21 d, arib 21 e, a rib 22 a, a rib 23 a) that prevents undesirable externallight from entering the composite lens barrel 10 even with a clearancetherebetween is provided at each edge portion of the upper wall 21, theside wall 22, and the side wall 23.

Specifically, as illustrated in FIGS. 16 and 17, the ribs 21 d and 21 eare disposed at the end of the top portion 21 a. The ribs 21 d and 21 eof the lens barrel 11A and the ribs 21 d and 21 e of the lens barrel 11Bhave relative positions to overlap with each other along the up-to-downdirection when the lens barrel 11A and the lens barrel 11B are combined.The ribs 22 a and 23 a are disposed at the ends of the side walls 22 andthe side walls 23 of the lens barrel 11A and the lens barrel 11B, andhave relative positions to overlap with each other along right-to-leftdirection when the lens barrel 11A and the lens barrel 11B are combined.With such an overlap, external light is blocked. As illustrated in FIGS.7, 11, and 17, a rib 21 f is disposed on the side portion 21 c andprojects backward from the top portion 21 a. When the lens barrel 11Aand the lens barrel 11B are combined, the rib 21 f overlaps with a partof the side portion 21 b of the corresponding lens barrel in theright-to-left direction (see FIG. 7). With such a configuration in whichthe rib 21 f overlaps with the side portion 21 b, external light isblocked.

As described above, the relative positions of the lens barrel 11A andthe lens barrel 11B in the front-to-back direction are determined by thecontact surface 50 contacting the contact surface 51. Further, apredetermined clearance is provided along the front-to-back directionbetween the lens barrel 11A and the lens barrel 11B in an area exceptthe areas of the contact surface 50 and the contact surface 51.

Each of the upper wall 35 a and the lower wall 35 b of the first prismholder 35 is formed such that the edge facing the back side has astepwise shape formed by continuous sets of a plane perpendicular to theoptical axis X1 and a plane parallel to the optical axis X1. When thelens barrel 11A and the lens barrel 11B are combined, the stepped edgeof the upper wall 35 a of one of the lens barrel 11A and the lens barrel11B is opposed to the stepped edge of the lower wall 35 b of the otherlens barrel 11A or 11B in the front-to-back direction with a slightclearance. When an excessive load (an excessive load in a direction inwhich the lens barrel 11A and the lens barrel 11B are brought together)is applied to the lens barrel 11A and the lens barrel 11B in thefront-to-back direction, the edge of the upper wall 35 a (the lower wall35 b) of the lens barrel 11A comes into contact with the edge of theupper wall 35 a (the lower wall 35 b) of the lens barrel 11B, whichreceives the load. That is, the opposing portions of the upper wall 35 aand the lower wall 35 b are used as an auxiliary contact surface todistribute the load between the lens barrel 11A and the lens barrel 11B,which strengthens the composite lens barrel 10 as a whole. Since theedges of the upper wall 35 a and the lower wall 35 b, i.e., the planesperpendicular to the optical axis X1 are opposed to each other,unnecessary component forces are not generated when the planes arebrought into contact, so that the loads are reliably received by theplanes. Particularly, the position at which the first prism holder 35 isprovided is around the intermediate position between the contact surface50 and the contact surface 51 which are significantly separatedright-to-left direction, and a position at which the first prisms AP1and BP1 are held having a significant influence on the opticalperformance. By receiving the load with the front and back load with thefirst prism holders 35 as an auxiliary tool, the strength of thecomposite lens barrel 10 as a whole is increased and the opticalperformance is obtained.

As described above, when the lens barrel 11A and the lens barrel 11B arecombined, the cylindrical portion 14 a of the rear group frame 14 fitsin the space between the rear group frame holder 37 and the rear groupframe accommodating section 42, which are opposed to each other in thefront-to-back direction. On the back side of the base frame 12, a reargroup frame opposing part 56 is formed in the rear group frame holder 37(see FIGS. 16 to 19). The rear group frame opposing part 56 is a planeperpendicular to the optical axis X1. As illustrated in FIG. 13, therear group frame 14 has an opposing convex portion 14 f on the frontside facing the rear group frame holder 37 of the base frame 12. Theopposing convex portion 14 f is provided at a position facing the reargroup frame opposing part 56 of the base frame 12 with the rear groupframe 14 attached to the base frame 12. In view of design, the opposingconvex portion 14 f is configured to contact the rear group frameopposing part 56. If there is a tolerance error that separates theopposing convex portion 14 f from the rear group frame opposing part 56,a flexible member is inserted between the base frame 12 and the reargroup frame 14 to give a biasing force to the rear group frame 14 so asto come into contact with the rear group frame opposing part, whichprovides a stable contact action. Specifically, when the opposing convexportion 14 f of the rear group frame 14 is separated from the rear groupframe opposing part 56 on the lens barrel 11A side, a flexible member isdisposed on the inner surface of the rear group frame accommodatingsection 42 of the base frame 12 on the lens barrel 11B side.Accordingly, the rear group frame 14 on the lens barrel 11A is pressedforward to make the opposing convex portion 14 f contact the rear groupframe opposing part 56. In such a manner, the position of the rear groupframe 14 is controlled with high accuracy in each of the lens barrels11A and 11B. Note that the positioning of the rear group frame 14 doesnot hamper the positioning of the lens barrels 11A and 11B using thecontact surfaces 50 and 51.

A description is given of a configuration that determines the positionsof the lens barrel 11A and the lens barrel 11B in a directionperpendicular to the optical axis X1. In this configuration, the baseframe 12 on the lens barrel 11A side is a supporting holder (which isreferred to simply as a holder) as a positioning reference, and the baseframe 12 on the lens barrel 11B is a supported lens barrel to bepositioned. The base frame 12 of each of the lens barrel 11A and lensbarrel 11B has a first hole 60 and a second hole 61. A first hole 60 isformed inside a cylindrical boss 62 projecting forward and backwardbeyond the corner wall 24, and a second hole 61 is formed inside acylindrical boss 63 projecting forward and backward beyond the cornerwall 25. The boss 62 is positioned above the boss 52 having the contactsurface 50, and the boss 63 is positioned above the boss 53 having thecontact surface 51. Both the first hole 60 and the second hole 61 arethrough-holes penetrating the base frame 12 in the front-to-backdirection. The first hole 60 and the second hole 61 are provided atsubstantially symmetrical positions (substantially equidistant from thevirtual plane Q1 in the right-right-to-left direction) with respect tothe virtual plane Q1 (FIG. 5) including the optical axis X1 andextending in the up-to-down direction.

The first hole 60 has a circular hole 60 a and an elongated hole 60 bwhich are communicable with each other in the front-to-back direction.The circular hole 60 a is positioned on the back surface of the baseframe 12, and the elongated hole 60 b is positioned on the front surfaceof the base frame 12. The circular hole 60 a is a circular hole having acylindrical inner peripheral surface around an axis oriented in thefront-to-back direction. The elongated hole 60 b is an elongated holehaving a long direction along the right-to-left direction (the radialdirection of the circular hole 60 a) perpendicular to the front-to-backdirection (the axial direction of the first hole 60), and has a pair ofparallel planes 60 c opposed to each other up-to-down direction inside.Each plane 60 c is a plane parallel to the optical axes X1, X2, and X4and perpendicular to the optical axis X3. The pair of planes 60 c areformed at positions vertically symmetrical about the axis of thecircular hole 60 a. As illustrated in FIGS. 22A, 22B, 26A, and 26B, thevertical dimension K2 (the distance between the pair of planes 60 c) ofthe elongated hole 60 b is smaller than the inner diameter K1 of thecircular hole 60 a. Further, the length M2 of the elongated hole 60 b inthe front-to-back direction is longer than the length M1 of the circularhole 60 a in the front-to-back direction.

The second hole 61 has a circular hole 61 a and a small diameter hole 61b which are communicable with each other in the front-to-back direction.The circular hole 61 a is positioned on the back surface of the baseframe 12, and the small diameter hole 61 b is positioned on the frontsurface of the base frame 12. Each of the circular hole 61 a and thesmall diameter hole 61 b is a circular hole having a cylindrical innerperipheral surface around an axis oriented in the front-to-backdirection. The circular hole 61 a and the small diameter hole 61 b havedifferent inner diameters. As illustrated in FIGS. 22A, 22B, 26A, and26B, the inner diameter K4 of the small diameter hole 61 b is smallerthan the inner diameter K3 of the circular hole 61 a The length M3 ofthe circular hole 61 a in the front-to-back direction is longer than thelength M4 of the elongated hole 60 b in the front-to-back direction.

In the first hole 60 and the second hole 61, the inner diameter K1 ofthe circular hole 60 a is substantially equal to the inner diameter K3of the circular hole 61 a, and the vertical width K2 of the elongatedhole 60 b is substantially equal to the inner diameter K4 of the smalldiameter hole 61 b. Regarding the length in the front-to-back directionis, the length M 3 of the circular hole 61 a is longer than the lengthM2 of the elongated hole 60 b. The length M2 of the elongated hole 60 bis longer than the length M1 of the circular hole 60 a. The length M1 ofthe circular hole 60 a is longer than the length M4 of the smalldiameter hole 61 b.

The entire length of the first hole 60 in the front-to-back direction issubstantially the same as the entire length of the second hole 61 in thefront-to-back direction. The first hole 60 has a tapered shape betweenthe circular hole 60 a and the elongated hole 60 b whose width graduallydecreases in a direction from the circular hole 60 a to the elongatedhole 60 b. The entire length of the first hole 60 includes the length ofthe tapered portion.

Shaft member 65 (a first shaft member) and the shaft member 66 (a secondshaft member) are inserted into the first hole 60 and the second hole 61of the base frame 12, respectively in each of the lens barrels 11A and11B. The shaft member 65 and the shaft member 66 are made of metal.FIGS. 22A, 22B, 26A, and 26B are enlarged views of the shaft member 65and the shaft member 66, respectively.

The shaft member 65 has a shaft portion 65 a (a first insertion section)and a shaft (a second insertion section) 65 b aligned in thefront-to-back direction, and a flange 65 c (one restriction part)between the shaft portion 65 a and the shaft portion 65 b. The shaftportion 65 a and the shaft portion 65 b have cylindrical outer surfacesaround the same axial line oriented in the front-to-back direction, andthe outer diameters of the shaft portion 65 a and the shaft portion 65 bare substantially equal. The flange 65 c has a larger diameter than theouter diameter of the shaft portion 65 a and the shaft portion 65 bdoes, and is an annular portion projecting from the outer surface of theshaft portion 65 a and the shaft portion 65 b.

The lengths of the shaft portion 65 a and the shaft portion 65 b in thefront-to-back direction are equal to each other, and are slightlyshorter than the length M1 of the circular hole 60 a in the first hole60. The shaft portion 65 a and the shaft portion 65 b are symmetrical inthe axial direction (the outer diameters and the lengths are the same)with respect to the flange 65 c. Accordingly, if the shaft member 65 isinverted back and forth so that the shaft portion 65 a faces the backside and the shaft portion 65 b faces the front side, the same structureis obtained.

The outer diameter of the shaft portion 65 a and the shaft portion 65 bis substantially equal to the inner diameter K1 of the circular hole 60a and the inner diameter K3 of the circular hole 61 a. Morespecifically, the outer diameter of the shaft portion 65 a and the shaftportion 65 b is slightly larger than the inner diameters K1 and K3, andboth the shaft portion 65 a and the shaft portion 65 b are inserted intothe circular hole 60 a and the circular hole 61 a with a light press-inforce.

The shaft member 66 includes a large diameter shaft 66 a (a first shaft)and a small diameter shaft 66 b (a second shaft) arranged in thefront-to-back direction, and a flange 66 c (the other restricting part)between the large diameter shaft 66 a and the small diameter shaft 66 b.The large diameter shaft 66 a and the small diameter shaft 66 b havecylindrical outer surfaces around the same axial line oriented in thefront-to-back direction. The outer diameter of the large diameter shaft66 a is larger than the outer diameter of the small diameter shaft 66 b.In addition, the length of the large diameter shaft 66 a in thefront-to-back direction is larger than the small diameter shaft 66 bdoes.

The large diameter shaft 66 a further includes a base end section 66 dclose to the flange 66 c and a tip section 66 e far from the flange 66c. The base end section 66 d has a larger outer diameter than the tipsection 66 e does. The entire length of the large diameter shaft 66 a(the sum of the lengths of the base end sections 66 d and the tipsection 66 e) in the front-to-back direction is longer than the totallength of the length M1 of the circular hole 60 a and the length M4 ofthe small diameter hole 61 b, and shorter than the total length of thelength M2 of the elongated hole 60 b and the length M3 of the circularhole 61 a. In addition, the length of the base end section 66 d in thefront-to-back direction is longer than the length of the tip section 66e.

The small diameter shaft 66 b further includes a base end section 66 fclose to the flange 66 c and a tip section 66 g far from the flange 66c. The base end section 66 f has a larger outer diameter than the tipsection 66 g does. The entire length of the small diameter shaft 66 b(the sum of the lengths of the base end sections 66 f and the tipsection 66 g) in the front-to-back direction is slightly longer than thetotal length of the circular hole 60 a, and is also slightly longer thanthe total length of the circular hole 61 a. In addition, the length ofthe base end section 66 f in the front-to-back direction is longer thanthe length of the tip section 66 g. The length of the base end sections66 f is longer than each of the length M1 of the circular hole 60 a, thelength M2 of the elongated hole 60 b, and the length M4 of the smalldiameter hole 61 b. The length of the base end sections 66 f is slightlyshorter than the length M3 of the circular hole 61 a. The length of thetip section 66 g is slightly larger than the length M4 of the smalldiameter hole 61 b and slightly smaller than the length M1 of thecircular hole 60 a.

The outer diameter of the large diameter shaft 66 a is substantiallyequal to the inner diameter K1 of the circular hole 60 a and the innerdiameter K3 of the circular hole 61 a. More specifically, the outerdiameter of the base end section 66 d of the large diameter shaft 66 ais slightly larger than the inner diameters K1 and K3, and the outerdiameter of the tip section 66 e is slightly smaller than the innerdiameters K1 and K3. Accordingly, the large diameter shaft 66 a isinserted into the circular hole 60 a or the circular hole 61 a with thebase end section 66 d lightly press-fit.

The outer diameter of the small diameter shaft 66 b is substantiallyequal to the vertical width K2 of the elongated hole 60 b and the innerdiameter K4 of the small diameter hole 61 b. More specifically, theouter diameter of the base end section 66 f of the small diameter shaft66 b is slightly larger than the vertical width K2 and the innerdiameter K4, and the outer diameter of the tip section 66 g is slightlysmaller than the vertical width K2 and the inner diameter K4.Accordingly, the small diameter shaft 66 b is inserted into theelongated hole 60 b or the small diameter hole 61 b with the base endsection 66 f lightly press-fit. However, actually, the insertion of thebase end section 66 f into the small diameter hole 61 b is restricted bythe flange 66 c (see FIG. 28).

In the drawings of the present embodiments, cases in which the positionof the lens barrel 11B is adjusted with reference to the lens barrel 11Aare illustrated. That is, cases in which the lens barrel 11A is areference supporting lens barrel and the lens barrel 11B is a supportedlens barrel to be positioned are described.

First, as illustrated in FIGS. 20A and 20B, the shaft portion 65 a ofthe shaft member 65 is inserted into the first hole 60 on the lensbarrel 11A side from the back side. The insertion of the shaft member 65is restricted at a position at which the flange 65 c contact the endface on the back side of the boss 62. Since the length of the shaftportion 65 a is smaller than the length M1 of the circular hole 60 a,the shaft portion 65 a is inserted to the circular hole 60 a withoutreaching the position of the elongated hole 60 b (see FIGS. 22A and22B). Since the outer diameter of the shaft portion 65 a is slightlylarger than the inner diameter K1 of the circular hole 60 a, the shaftportion 65 a is lightly press-fit by the circular hole 60 a, and theshaft member 65 is stably mounted onto the base frame 12 on the lensbarrel 11A side without rattling.

Further, as illustrated in FIGS. 24A and 24B, the large diameter shaft66 a of the shaft member 66 is inserted into the second hole 61 on thelens barrel 11A side from the back side. The insertion of the shaftmember 66 is restricted at a position where the flange 66 c comes intocontact with the end face on the back side of the boss 63. Since thelength of the large diameter shaft 66 a is smaller than the length M3 ofthe circular hole 61 a, the large diameter shaft 66 a is inserted to thecircular hole 61 a without reaching the position of the small diameterhole 61 b (see FIGS. 26A and 26B). Since the outer diameter of the baseend section 66 d is slightly larger than the inner diameter K3 of thecircular hole 61 a, the large diameter shaft 66 a is lightly press-fitby the circular hole 61 a, and the shaft member 66 is stably mountedonto the base frame 12 on the lens barrel 11A side without rattling.

Since the outer diameter of the tip section 66 e of the large diametershaft 66 a is slightly smaller than the inner diameter K3 of thecircular hole 61 a, the large diameter shaft 66 a is smoothly insertedinto the circular hole 61 a without being press-fit at the initial stageof insertion. In other words, the large diameter shaft 66 a isconfigured to be press-fit at the final stage of insertion at which astable support is needed, which facilitates improves insertion.

FIG. 19 is an illustration of the shaft member 65 and the shaft member66 attached to the base frame 12 on the lens barrel 11A side. As can beseen from FIG. 19, the shaft portion 65 b of the shaft member 65 and thesmall diameter shaft 66 b of the shaft member 66 project backward (tothe back side of the lens barrel 11A).

The shaft member 65 and the shaft member 66 are attached to the lensbarrel 11A at any desired timing. For example, as illustrated in FIG.19, the shaft member 65 and the shaft member 66 are attached to asimplex base frame 12 in advance, and subsequently other components (forexample, the rear group frame 14, the third prism frame 15, and theimage sensor unit 16) are attached to the base frame 12. Alternatively,the components other than the shaft member 65 and the shaft member 66are first attached to the base frame 12, and then the shaft member 65and the shaft member 66 are attached to the base frame 12. In eithercase, since the shaft member 65 and the shaft member 66 are press-fit bythe base frame 12, there is no possibility that the shaft member 65 andthe shaft member 66 might fall accidentally after assembling. The firsthole 60 and the second hole 61, into which the shaft member 65 and theshaft member 66 are inserted, are positioned on an upper end of the baseframe 12, the upper end being away from the first prism holder 35, thesecond prism holder 36, the rear group frame holder 37, and the reargroup frame accommodating section 42. With such an arrangement, afterassembling the components other than the shaft members 65 and 66 to thebase frame 12, it is still easy to access the first hole 60 and thesecond hole 61 to assemble the shaft members 65 and 66.

Subsequently, the lens barrel 11B is attached to the lens barrel 11A inwhich the shaft member 65 and the shaft member 66 are assembled. Thesecond hole 61 (circular hole 61 a) on the lens barrel 11B side isopposed to the shaft portion 65 b of the shaft member 65, and the firsthole 60 (circular hole 60 a) on the lens barrel 11B side is opposed tothe small diameter shaft 66 b of the shaft member 66. That is, thecircular hole 60 a on the lens barrel 11A side and the circular hole 61a on the lens barrel 11B side are a pair of holes opposed to each otherin the front-to-back direction, and the circular hole 61 a on the lensbarrel 11A side and the circular hole 60 a on the lens barrel 11B is apair of holes opposed to each other in the front-to-back direction. Whenthe lens barrel 11A and the lens barrel 11B are brought together in thefront-to-back direction, the shaft portion 65 b is inserted into thesecond hole 61 of the lens barrel 11B (FIG. 21), and the small diametershaft 66 b is inserted into the first hole 60 of the lens barrel 11B(FIG. 25).

As described above, the contact surfaces 50 and 51 of the lens barrels11A and 11B contact each other, which restricts further approach (thepositions of the lens barrel 11A and the lens barrel 11B in thefront-to-back direction is determined). As illustrated in FIGS. 22A,22B, 26A, and 26B, when the contact surface 50 contacts the contactsurface 51, there is a gap N in the front-to-back direction between theopposing end faces of the boss 62 and 63 on the base frames 12 of thelens barrels 11A and 11B. The thickness of each of the flange 65 c ofthe shaft member 65 and the flange 66 c of the shaft member 66 isslightly smaller than the gap N. Accordingly, the shaft member 65 andthe shaft member 66 do not hamper positioning of the lens barrels 11Aand 11B in the front-to-back direction using the contact surfaces 50 and51.

As illustrated in FIGS. 22A and 22B, since the length of the shaftportion 65 b is shorter than the length M3 of the circular hole 61 a,the shaft portion 65 b is inserted to the circular hole 61 a withoutreaching the position of the small diameter hole 61 b in the second hole61 on the lens barrel 11B side. Since the circular hole 61 a of thecylindrical inner surface fits to the shaft portion 65 b of thecylindrical outer surface, the movement of the base frame 12 on the lensbarrel 11B side in the radial direction of the shaft portion 65 b (allthe direction perpendicular to the direction in which the first hole 60and the second hole 61 are opposed to each other (the optical axis X1))is restricted. With such a configuration, the relative positions of thelens barrel 11A and the lens barrel 11B are determined within a planeperpendicular to the optical axis X1.

Since the outer diameter of the shaft portion 65 b is slightly largerthan the inner diameter K3 of the circular hole 61 a, the shaft portion65 b is lightly press-fit by the circular hole 61 a. Accordingly, withthe lens barrel 11A and the lens barrel 11B combined, the shaft member65 might not rattle and generate abnormal noise.

As illustrated in FIGS. 26A and 26B, the small diameter shaft 66 b isinserted from the circular hole 60 a side to the elongated hole 60 b soas to be inserted into the first hole 60 on the lens barrel 11B side.Since the outer diameters of the base end section 66 f and the tipsection 66 g are both smaller than the inner diameter K1 of the circularhole 60 a, the small diameter shaft 66 b does not contact the innersurface of the first hole 60 in the initial stage of insertion.

When the small diameter shaft 66 b moves deeper inside of the first hole60, the tip section 66 g of the small diameter shaft 66 b enters theelongated hole 60 b. Since the outer diameter of the tip section 66 g issmaller than the vertical width K2 of the elongated hole 60 b, no loadis generated between the shaft member 66 and the first hole 60 at thisstage. When the small diameter shaft 66 b moves still further inside ofthe first hole 60, the base end section 66 f of the small diameter shaft66 b enters the elongated hole 60 b. Then, the base end section 66 f issandwiched between a pair of up and down planes 60 c in the elongatedhole 60 b, and accordingly a vertical movement of the base frame 12 onthe lens barrel 11B side is restricted with respect to the smalldiameter shaft 66 b. As a result, the rotation of the lens barrel 11Arelative to the lens barrel 11B around the shaft member 65 isrestricted.

Further, since the length of the elongated hole 60 b in theright-to-left direction is larger than the outer diameter of the baseend section 66 f, the small diameter shaft 66 b does not restrict theposition of the lens barrel 11B in the right-to-left direction. That is,the elongated hole 60 b of the lens barrel 11B is movable relative tothe small diameter shaft 66 b only in a certain direction (theright-to-left direction) within a plane perpendicular to the directionin which the first hole 60 and the second hole 61 are opposed to eachother (the direction along the optical axis X1). With such aconfiguration, the small diameter shaft 66 b and the first hole 60 workto cancel out the assembly tolerances between the lens barrel 11A andthe lens barrel 11B.

Note that since the outer diameter of the base end section 66 f isslightly larger than the vertical width K 2 of the elongated hole 60 b,the small diameter shaft 66 b is lightly press-fitted into the elongatedhole 60 b. Accordingly, with the lens barrel 11A and the lens barrel 11Bcombined, the shaft member 66 might not rattle and generate abnormalnoise. As described above, since the tip section 66 g is provided at thetip end of the small diameter shaft 66 b, no press-fitting occurs untilthe small diameter shaft 66 b is advanced to some extent inside theelongated hole 60 b. With this configuration, the timing at which thesmall diameter shaft 66 b (base end section 66 f) of the shaft member 66is press-fitted into the elongated hole 60 b of the first hole 60becomes substantially the same as the timing at which the shaft portion65 b of the shaft member 65 is press-fitted into the circular hole 61 aof the second hole 61. Accordingly, the lens barrel 11B is combined withthe lens barrel 11A without being tilted. Unlike the present embodiment,if the tip section 66 g is not provided in the small diameter shaft 66 band the small diameter shaft 66 b as a whole has the same diameter asthat of the base end section 66 f, the timing at which the smalldiameter shaft 66 b is press-fit into the elongated hole 60 b of thefirst hole become significantly earlier than the timing at which theshaft portion 65 b is press-fit into the circular hole 61 a of thesecond hole 61. Accordingly, the lens barrel 11B is likely to be tiltedrelative to the lens barrel 11A with the location of the shaft member 66and the first hole 60 as a fulcrum.

As illustrated in FIGS. 26A and 26B, since the length of the smalldiameter shaft 66 b is slightly longer than the entire length of thefirst hole 60, the small diameter shaft 66 b passes through the firsthole 60 on the lens barrel 11B side so that the tip section 66 gprojects to the back side of the lens barrel 11A beyond the boss 63.With such a configuration, although the lens barrel 11A and the lensbarrel 11B have the same symmetrical shape along the front-to-backdirection, it is easier to identify the front side of the lens barrel11B at which the shaft member 66 projects beyond the boss 63, whichimproves the workability.

As described above, the shaft member 65 and the shaft member 66 arepress-fit into the first hole 60 and the second hole 61, respectively.However, if the load of press-fitting is too large, workabilitydeteriorates or distortion occurs on the base frame 12 side, which mightaffect positioning accuracy. In order to avoid such a situation, therelative diameters of the first hole 60, the second hole 61, and theshaft members 65 and 66 are set so as to be slightly press fit withoutimpairing the positioning accuracy.

The positions at which the shaft member 65 and the shaft member 66 arepositioned are close to the positions at which positioning is made bythe contact surface 50 and the contact surface 51 along thefront-to-back direction. The shaft member 65 and the shaft member 66 aredisposed substantially symmetrically with respect to the virtual planeQ1 (FIG. 5) that includes the optical axis X1 and extends along theup-to-down direction. With such a configuration in which the distancebetween the shaft member 65 and the shaft member 66 along theright-to-left direction is increased, and in which the shaft member 65and the shaft member 66 are disposed symmetrically in positions relativeto the front group AF and BF and the first prisms AP1 and BP1, theaccuracy of positioning is increased.

The first hole 60 and the second hole 61 into which the shaft member 65and the shaft member 66 are inserted are arranged in the corner wall 24and the corner wall 25, respectively of the base frame 12, which enablesspace to be efficiently utilized without interfering with the othercomponents constituting the lens barrel 11A and lens barrel 11B. Inaddition to the rigidity of the corner walls 24 and 25, the thickness ofthe boss 62 having the first hole 60 and the boss 63 having the secondhole 61 also provide reinforcement. Accordingly, the first hole 60 andthe second hole 61 are not likely to be displaced by using the shaftmember 65 and the shaft member 66.

The first hole 60 and the second hole 61 are also used to attach anexterior member attaching an exterior member constituting the outersurface of the imaging apparatus 80 thereto. The front cover 70 in FIGS.23 and 27 is an exterior member that covers the front side of theimaging apparatus 80. The front cover 70 has a support protrusion 71(FIG. 23) projecting backward and a support protrusion 72 (FIG. 27) onthe inner surface side. The support protrusion 71 and the supportprotrusion 72 are provided to correspond to the first hole 60 and thesecond hole 61 in the base frame 12, respectively. The supportprotrusion 71 has a cylindrical outer surface portion having a constantouter diameter around the tip of the support protrusion 71. The outerdiameter of the cylindrical outer surface is substantially the same asthe vertical width K2 of the elongated hole 60 b in the first hole 60.The support protrusion 72 has a cylindrical outer surface portion havinga constant outer diameter around the tip portion of the supportprotrusion 72. The outer diameter of the cylindrical outer surfaceportion is substantially the same as the vertical width K4 of the smalldiameter hole 61 b in the second hole 61.

In attaching the front cover 70 to the composite lens barrel 10, the tipportion (cylindrical outer surface portion) of the support protrusion 71is inserted from the front side into the elongated hole 60 b of thefirst hole 60 on the lens barrel 11A side. Further, the tip portion(cylindrical outer surface portion) of the support protrusion 72 isinserted from the front side into the small diameter hole 61 b of thesecond hole 61 on the lens barrel 11A side. On the lens barrel 11A, theshaft portion 65 a of the shaft member 65 has not entered the elongatedhole 60 b yet, and the large diameter shaft 66 a of the shaft member 66has not entered the small diameter hole 61 b yet either. Accordingly,the support protrusion 71 and the support protrusion 72 are successfullyinserted into the first hole 60 and the second hole 61, respectivelywithout interfering with the shaft member 65 and the shaft member 66.

The support protrusion 72 of the cylindrical outer surface fits thesmall diameter hole 61 b of the cylindrical inner surface, so that thefront cover 70 is positioned within a plane perpendicular to the opticalaxis X1. Further, the support protrusion 71 is sandwiched between thepair of planes 60 c of the elongated hole 60 b, which restrict therotation of the front cover 70 around the support protrusion 72. Thelength of the elongated hole 60 b in the right-to-left direction islonger than the outer diameter of the support protrusion 71, and theposition of the support protrusion 71 in the right-to-left direction isnot restricted by the elongated hole 60 b. With such a configuration,the support protrusion 71 and the first hole 60 work to cancel outassembly tolerances of assemble of the front cover 70 and the compositelens barrel 10. In that manner, the first hole 60 and the second hole 61are used to position the shaft member 65 and the shaft member 66 andalso used to assemble and position the front cover 70.

In the lens barrel 11B side, the small diameter shaft 66 b of the shaftmember 66 passes through the first hole 60 as a whole (see FIGS. 26A and26B), whereas the shaft member 65 has not entered the small diameterhole 61 b of the second hole 61 yet (FIGS. 22A and 22B). Accordingly, aprotrusion of another member (for example, a back cover constituting anexterior component of the imaging apparatus 80 together with the frontcover 70) is inserted from the back side into the small diameter hole 61b of the lens barrel 11B so as to position the another member.

As the shaft member 65 has a symmetrical shape in the axial direction,the orientations of the shaft portion 65 a and the shaft portion 65 bmay be reversed. However, as the shaft member 66 has an asymmetricalshape along the axial direction, the large diameter shaft 66 a and thesmall diameter shaft 66 b, whose orientations are reversed, fail inassembly and malfunction. The imaging apparatus 80 according to thepresent embodiment has a structure that prevents the shaft member 66from being assembled in an opposite direction.

FIG. 28 is an illustration of a case in which the shaft member 66 isassembled in the opposite direction. The small diameter shaft 66 b isinserted into the second hole 61 on the lens barrel 11A. The outerdiameter of the base end section 66 f of the small diameter shaft 66 bis shorter than the inner diameter K3 of the circular hole 61 a, and theouter diameter of the tip section 66 g is shorter than the innerdiameter K4 of the small diameter hole 61 b. With such a configuration,the small diameter shaft 66 b can be advanced inside the second hole 61to reach the position at which the flange 66 c contacts the back-sideend face of the boss 63.

The length of the large diameter shaft 66 a is longer than the length M1of the circular hole 60 a of the first hole 60. Accordingly, when thelarge diameter shaft 66 a is inserted into the first hole 60 of the lensbarrel 11B side, the tip of the large diameter shaft 66 a abuts againstthe step in the boundary between the circular hole 60 a and theelongated hole 60 b earlier than the contact surfaces 50 and 51 contacteach other. Thus, further insertion is restricted. In this state, thereis a large gap in the front-to-back direction between the flange 66 cand the boss 63, which allows for recognition that the lens barrel 11Aand the lens barrel 11B are prevented from being close to each other dueto the assembly failure of the shaft member 66.

In assembling the front cover 70 (FIG. 23 and FIG. 27) to the compositelens barrel in the state of FIG. 28, the support protrusion 72 abutsagainst the small diameter shaft 66 b, so that the support protrusion 72fails to be inserted into the second hole 61 (the small diameter hole 61b). Accordingly, the front cover 70 is not fit into the front-sidecomposite lens barrel 10, which also allows for recognition that theshaft member 66 fails in assembly.

In the present embodiment, the case in which the lens barrel 11B ispositioned with reference to the lens barrel 11A side is described.However, in some embodiments, the lens barrel 11A may be positioned withreference to the lens barrel 11B because the lens barrel 11A and thelens barrel 11B have the same shape. In other words, it is also possibleto reverse the supporting lens barrel as the reference for positioning(the base frame 12 as the supporting holder (a holder)) and thesupported lens barrel (the base frame 12 as the supported holder(another holder)) to be positioned by the support barrel. Specifically,the shaft member 65 (which may be either of the shaft portion 65 a andthe shaft portion 65 b) is inserted into the first hole 60 (the circularhole 60 a) on the lens barrel 11B, and the large diameter shaft 66 a ofthe shaft member 66 is inserted into the second hole 61 (the circularhole 61 a) on the lens barrel 11B side. Subsequently, the shaft member65 (one of the shaft portion 65 a and the shaft portion 65 b that is notinserted into the first hole 60 of the lens barrel 11B) is inserted intothe second hole 61 (the circular hole 61 a) on the lens barrel 11A side,and the small diameter shaft 66 b of the shaft member 66 is insertedinto the first hole 60 (the elongated hole 60 b) on the lens barrel 11Aside.

In the present embodiment as described above, the lens barrel 11Aincluding the wide-angle lens system A and the image sensor AI iscombined with the lens barrel 11B including the wide-angle lens system Band the image sensor BI to constitute the composite lens barrel 10. Eachimaging system is housed in a corresponding lens barrel 11A/11B, whichfacilitates assembling the optical components in each of the lensbarrels 11A and 11B, and thus increases the productivity. Further, twolens barrels whose imaging performances are similar are selected as thelens barrel 11A and the lens barrel 11B to be combined. Accordingly, itis easy to control the performance of the imaging system 1 as a whole.In a mode that assembles a plurality of optical systems in one lensbarrel, when any failure is found in one optical system after theassembly of the lens barrel is completed (in particular, after the partsare fixed by, for example, adhesion), the entire system including theother optical systems with no failure has to be discarded, resulting inwaste. However, the configuration according to the embodiments of thepresent disclosure that combines the lens barrel 11A and the lens barrel11B is advantageous to an increase in productivity and a reduction incost without any waste.

In such a configuration according to the embodiments of the presentdisclosure, the two lens barrels 11A and 11B are positioned in thedirection perpendicular to the optical axis X1 using the shaft member 65and the shaft member 66 such that the lens barrel 11A and the lensbarrel 11B are opposed to each other. The shaft member 65 serves as amain-reference positioning mechanism that restricts the movement of thefirst hole 60 and the second hole 61 of each of the lens barrels 11A and11B along the all the direction perpendicular to the optical axis X1.The shaft member 66 serves as a sub-reference positioning mechanism thatallows the first hole 60 to move along a certain direction perpendicularto the optical axis X1 and restricts movement in the other directions.With this configuration, an error between the lens barrels 11A and 11Bis cancelled out and a high accuracy of positioning is achieved whilethe lens barrel members constituting the lens barrel 11A and the lensbarrel 11B (in particular, the base frame 12 to be positioned) have thesame shape.

Each of the first hole 60 and the second hole 61 has a simple shape inwhich the opening area inside consists of two phases, and is easilymanufactured when the base frame 12 is formed. The first hole 60 and thesecond hole 61 in the lens barrel 11A and the second hole 61 and thefirst hole 60 in the lens barrel 11B are opposed to each other,respectively. The shaft members 65 and 66 are inserted into these holesso that the lens barrel 11A and the lens barrel 11B are positioned. Thatis, the lens barrel 11A and the lens barrel 11B are easily assembledwithout complicated work.

As described above, either one of the lens barrel 11A and the lensbarrel 11B may be selected as the reference supporting lens barrel.Further, the imaging apparatus 81 has the structure that allows theworker to easily recognize a proper manner to assemble the shaft member66 having an asymmetrical shape along the axial direction in the lensbarrels 11A and 11B (see FIG. 28). Accordingly, wrong installation ofthe components in combining the lens barrels 11A and 11B can be avoided.

As the lens barrel 11A and the lens barrel 11B have the same shape as awhole including the first hole 60 and the second hole 61, it is possibleto reduce the number of parts, manufacturing cost, and time as comparedwith a configuration in which a plurality of lens barrels havingdifferent structures are combined. Further, in this configuration, theshaft members 65 and 66 are directly inserted into the first holes 60and the second holes 61 of the base frames 12 constituting the lensbarrel 11A and the lens barrel 11B so as to position the lens barrel 11Aand lens barrel 11B. This configuration provides a low-cost and simplestructure of the lens barrel and facilitates accuracy control betweenthe lens barrels, as compared to a configuration that includes anotherlarge member on which two lens barrels are mounted.

With reference to FIGS. 35 and 36, a description is given of the overallconfiguration of a full-view spherical imaging apparatus to which theimaging system 1 and the composite lens barrel 10 according to anembodiment of the present disclosure are applied. FIGS. 35 and 36 areillustrations of a typical configuration of a spherical imaging systemalthough the wide-angle lens systems A and B and the image sensors AIand BI are differently arranged from the above-described composite lensbarrel 10. The characteristic configurations of the imaging opticalsystem (the optical system), the imaging system, and the imagingapparatus are as described above (FIGS. 1 to 34).

As illustrated in FIG. 35, the imaging apparatus 80 includes an imagingbody 81, a casing 82 that holds components such as the imaging body 81,a controller, and a battery inside, and a shutter button 83 provided onthe outer surface of the casing 82. The casing 82 includes an exteriorcomponent that corresponds the front cover 70 according to theabove-described embodiment. In FIG. 35, although only the image-formingoptical systems 84A and 84B and the solid-state image sensors 85A and85B are illustrated within the casing 82 of the imaging apparatus 80,the structure that corresponds to the composite lens barrel 10 accordingto the above-described embodiments (FIGS. 1 to 34) is actually mountedwithin the casing 82.

The imaging body 81 in FIG. 35 corresponds to the imaging system 1 ofthe composite lens barrel 10. The imaging body 81 includes twoimage-forming optical systems 84A and 84B and two solid-state imagesensors 85A and 85B. Examples of the two solid-state image sensors 85Aand 85B include charge-coupled devices (CCDs) and complementary metaloxide semiconductors (CMOSs). A combination of one image-forming opticalsystem 84A/84B and one solid-state image sensor 85A/85B constitutes theimaging system. Each of the image-forming optical systems 84A and 84B isconfigured as a fish-eye lens consisting of, for example, seven lensesin six groups. In the embodiment illustrated in FIG. 35, the fish-eyelens has an wide angle of view of 180 (360/n, n is 2) degrees or more,preferably 185 degrees or more, and more preferably 190 degrees or more.

The positions of the optical elements (the lens, the prism, the filter,and the aperture stop) of the two image-forming optical systems 84A and84B are defined relative to the solid-state image sensor 85A and 85B.Such positions are defined such that the optical axes of the opticalelements of the image-forming optical systems 84A and 84B are orthogonalto the central portion of the light-receiving areas of the correspondingsolid-state image sensors 85A and 85B, and such that eachlight-receiving area serves as an image-forming plane of thecorresponding fish-eye lens. Each of the solid-state image sensors 85Aand 85B is a two-dimensional solid-state image sensor defines alight-receiving area. The solid-state image sensors 85A and 85B convertlight focused by the image-forming optical systems 84A and 84B intoelectrical signals, respectively.

In the imaging apparatus 80 illustrated in FIG. 35, the image-formingoptical systems 84A and 84B have the same specification, and arecombined to face in opposite directions from each other with the opticalaxes matching with each other. Each of the solid-state image sensors 85Aand 85B converts a received light distribution into an image signal andoutputs the signal to an image processing unit on the controller. Theimage processing unit joins partial-view images transmitted from thesolid-state image sensors 85A and 85B to obtain an image with a solidangle of 4π steradian (referred to as “spherical image” below). Theomnidirectional image is an image of all the directions that can be seenfrom an image capturing point. In the embodiment illustrated in FIG. 35,the imaging optical system generates a spherical image. However, in someother embodiments, the imaging optical system may generate a panoramicimage by capturing 360 degrees in a horizontal plane.

In the imaging optical system, the scan direction of the solid-stateimage sensor 85A is identical with the scan direction of the solid-stateimage sensor 85B, which enables images captured by the solid-state imagesensors 85A and 85B to be joined easier. That is, the scan directionsand scan sequences of the solid-state image sensors 85A and 85B areidentical with each other at portions to be joined together. Thisconfiguration is advantageous to joining images of an object,particularly a moving object on the boundary between two capturingranges of the camera. For example, when an upper-left portion of theimage captured by the solid-state image sensor 85A matches a lower-leftportion of the image captured by the solid-state image sensor 85B tojoin the images, the solid-state image sensor 85A scans the image fromright to left while scanning from top to bottom of the solid-state imagesensor 85A. The solid-state image sensor 85B scans from bottom to topwhile scanning from the right to the left of the solid-state imagesensor 85B. That is, the scan directions of the respective solid-stateimage sensors 85A and 85B are caused to match each other based on theportions of the images to be joined, which facilitates the joining ofthe images.

As described above, since the fish-eye lens has a full angle of viewexceeding 180 degrees, the images captured by the respective imagingoptical systems A and B partly overlap with each other. Accordingly, thecaptured images are joined with each other based on the overlappingportions of the images as reference data representing the identicalimage, so as to generate a full-view spherical image. The generatedspherical image is transmitted to a display device provided on orconnected to the imaging body 81, a printing device, and an externalmemory such as an SD (registered trademark) card and a compact flash(registered trademark).

FIG. 10 is a block diagram of an example of a hardware configuration ofthe imaging apparatus 80. The imaging apparatus 80 includes a digitalstill camera processor (hereinafter, simply referred to as a processor)500, a barrel unit 502, and various components connected to theprocessor 500. The barrel unit 502 includes the two image-formingoptical systems 84A and 84B and the solid-state image sensors 85A and85B. The solid-state image sensors 85A and 85B are controlled bycommands from the CPU 530 in the processor 500, which will be describedlater.

The processor 500 includes image signal processors (ISPs) 508A and 508B,a direct memory access controller (DMAC) 510, an arbiter (ARBMEMC) 512for arbitrating memory access, a memory controller (MEMC) 514 forcontrolling memory access, and a distortion correction/image compositeblock 518. The ISPs 508A and 508B apply white balance correction andgamma correction to the image signals processed by the solid-state imagesensors 85A and 85B. The MEMC 514 is coupled to a synchronous dynamicrandom access memory (SDRAM) 516. The SDRAM 516 temporarily stores datawhen the ISPs 508A and 508B and the distortion correction/imagecomposite block 518 perform processing. The distortion correction/imagecomposite block 518 applies distortion correction and top-bottomcorrection to the partial images captured by the imaging opticalsystems, using data from a triaxial accelerometer 520, so as tocomposite the images.

The processor 500 further includes a DMAC 522, an image processing block524, the CPU 530, an image data transferring unit 526, a synchronousdynamic random access memory (SDRAM) 528, a memory card controllingblock 540, a universal serial bus (USB) block 546, a peripheral block550, a sound unit 552, a serial block 558, a liquid crystal display(LCD) driver 562, and a bridge 568.

The CPU 530 controls operations of respective elements in the imagingapparatus 80. The image processing block 524 performs various types ofimage processes on image data using a resize block 532, a jointphotographic experts group (JPEG) block 534, and H. 264 block 536. Theresize block 532 enlarges or reduces the size of the image data byinterpolation processing. The JPEG block 534 is a codec block thatperforms JPEG compression and decompression. The H.264 block 536 is acodec block that compresses and decompresses a moving image such asH.264. The image data transferring unit 526 transfers the image on whichthe image processing has been performed by the image processing block524. The SDRAMC 528 controls an SDRAM 538 coupled to the processor 500,and the SDRAM 538 temporarily stores image data when various processingis performed on the image data in the processor 500.

The memory card controlling block 540 controls reading and writingfrom/to a memory card and a flash read only memory (ROM) 544 insertedinto the memory card slot 542. The memory card slot 542 is a slot todetachably attach a memory card to the imaging apparatus 80. The USBblock 546 controls USB communication to an external device such as apersonal computer coupled via the USB connector 548. The peripheralblock 550 is coupled to a power switch 566. The sound unit 552 iscoupled to a microphone 556 that receives an audio signal from a userand a speaker 554 that outputs the recorded audio signal and controlssound input and output. The serial block 558 controls serialcommunication with an external device such as a personal computer and iscoupled to a wireless Network Interface Card (NIC) 560. The LiquidCrystal Display (LCD) driver 562 is a driver circuit that drives an LCDmonitor 564 and performs conversion to a signal used to display variousstates on the LCD monitor 564.

The flash ROM 544 stores a control program written in a code that can bedecoded by the CPU 530 and various parameters. When the power is turnedon by the operation of a power switch 566, the control program mentionedabove is loaded into the main memory. The CPU 530 controls operation ofeach part in the imaging system 1 according to the program loaded intothe main memory, while temporarily saving data necessary for control onthe SDRAM 538 and a local static random access memory (SRAM).

In the above-described embodiment, the circular holes (the circularholes 60 a and 61 a) and the shafts (the shafts 65 a and 65 b) havingthe circular cross-sectional area constitute the main-referencepositioning mechanism positioning mechanism. Unlike this configuration,other types of holes and shafts having other cross-sectional shape otherthan the circle may constitute the main-reference positioning mechanism.FIGS. 37 to 44 are illustrations of variations in which the internalshapes of the hole are different. In each of the following variations,the same elements as those of the above-described embodiments areindicated with the same reference numerals, and description thereof isomitted. The shaft member 65 and the shaft member 66 are the same asthose of the above embodiments.

FIGS. 37 and 38 are illustrations of a positioning mechanism accordingto a first variation of an embodiment of the present disclosure. In thefirst variation, a first hole 160 has an opposing hole portion 90 as asubstitute for the circular hole 60 a of the above-described embodiment,and a second hole 161 has an opposing hole portion 91 as a substitutefor the circular hole 61 a of the above-described embodiment.

The opposing hole portion 90 of the first hole 160 includes acylindrical portion 90 a having a cylindrical inner surface and fourprotrusions 90 b projecting inward from the inner surface of thecylindrical portion 90 a. Each protrusion 90 b has a curved surface thatis convex toward the inner diameter direction, and this curved surfacehas a uniform cross-sectional shape continuing in the axial direction(the front-to-back direction) of the first hole 160. The fourprotrusions 90 b are disposed at substantially equal angular intervals(90° intervals) in the circumferential direction around the axis of thefirst hole 160, and the respective protrusion amounts are equal. Two ofthe protrusions 90 b are spaced apart and opposed to each other in along direction (the right-to-left direction) of the elongated hole 60 b.The remaining two protrusions 90 b are spaced apart and opposed to eachother in the width direction (the up-to-down direction) of the elongatedhole 60 b. The width between the opposed protrusions 90 b in theup-to-down direction and the width between the opposed protrusions 90 bin the right-to-left direction (the distance between peaks of the convexsurfaces of the opposed protrusions 90 b). The distance between the twoprotrusions 90 b opposed to each other in the width direction (theup-to-down direction) of the elongated hole 60 b is longer than thedistance between the pair of planes 60 c in the elongated hole 60 b.

On the lens barrel 11A side, the shaft portion 65 a of the shaft member65 is inserted into the opposing hole portion 90 of the first hole 160.The virtual circle indicated by a two-dot chain in FIG. 37 is anincircle that internally contacts the four protrusions 90 b of theopposing hole portion 90. That is, the shaft portion 65 a of the shaftmember 65 has a diameter of the circle. In this contact state, the shaftportion 65 a is lightly press-fitted into the opposing hole portion 90.That is, the distance between the opposed protrusions 90 b is slightlysmaller than the diameter of the shaft portion 65 a at the initialstate. The shaft portion 65 a contacts each of the protrusions 90 b in alinear region along the axial direction of the first hole 160. The shaftportion 65 a does not contact each of the cylindrical portion 90 a.Accordingly, the contact area between the shaft portion 65 a and theopposing hole portion 90 is reduced, and thus a load imposed byinsertion of the shaft portion 65 a is reduced as compared to theconfiguration in which substantially the entire outer surface of theshaft portion 65 a contacts the inner surface of the hole. Further, sucha configuration according to the present embodiment reduces or preventstilting of the shaft portion 65 a, and also advantageously advances theshaft portion 65 a inside the first hole 160 in the axial direction.

On the lens barrel 11B side, the small diameter shaft 66 b of the shaftmember 66 is inserted into the first hole 160. In the opposing holeportion 90, each of the distance between the two protrusions 90 bopposed to each other right-to-left direction and the distance betweenthe two protrusions 90 b opposed to each other in the up-to-downdirection is shorter than the diameter of the small diameter shaft 66 b(the base end section 66 f and the tip section 66 g). Accordingly, eachprotrusion 90 b does not hamper the insertion of the small diametershaft 66 b into the first hole 160.

Similarly to the opposing hole portion 90 of the first hole 160, theopposing hole portion 91 of the second hole 161 has a cylindricalportion 91 a having a cylindrical inner surface and four protrusions 91b projecting inward from the inner surface of the cylindrical portion 90a. The shape (inner diameter) of the cylindrical portion 91 a and thearrangement and shape of each protrusion 91 b are the same as those ofthe cylindrical portion 90 a and each protrusion 90 b of the opposinghole portion 90. The four protrusions 91 b are disposed at substantiallyequal angular intervals (90° intervals) in the circumferential directionaround the axis of the second hole 161. Two of the protrusions 91 b arespaced apart and opposed to each other up-to-down direction, and theremaining two protrusions 91 b are spaced apart and opposed to eachother along the right-to-left direction. Each distance between the twoopposed protrusions 91 b is greater than the diameter of the smalldiameter hole 61 b of the second hole 161.

On the lens barrel 11A side, the large diameter shaft 66 a of the shaftmember 66 is inserted into the opposing hole portion 91 of the secondhole 161. On the lens barrel 11B side, the shaft portion 65 b of theshaft member 65 is inserted into the opposing hole portion 91 of thesecond hole 161. The virtual circle indicated by a two-dot chain in FIG.37 is an incircle that internally contacts the four protrusions 90 b ofthe opposing hole portion 90. That is, each of the shaft portion 65 band the large diameter shaft 66 a (the base end section 66 d) of theshaft member 65 has a diameter of the circle. In this contact state,each of the shaft portion 65 b and the large diameter shaft 66 a (thebase end section 66 d) is lightly press-fitted into the opposing holeportion 90. In other words, the distance between the opposed protrusions91 b is slightly smaller than the diameter of each of the shaft portion65 b and the base end section 66 d at the first stage of insertion. Theshaft portion 65 b and the large diameter shaft 66 a (the base endsection 66 d) contact each of the protrusions 90 b in a linear regionalong the axial direction of the second hole 161. Neither the shaftportion 65 b nor the large diameter shaft 66 a contacts the cylindricalportion 91 a. Accordingly, the contact area of the opposing hole portion91 contacting the shaft portion 65 b and the large diameter shaft 66 a(the base end section 66 d) is reduced, and thus a load imposed byinsertion of the shaft portion 65 b and the large diameter shaft 66 a(the base end section 66 d) is reduced. Further, such a configurationthat includes the plurality of protrusions 91 b reduces or preventstilting of the shaft portion 65 a, and also advantageously advances theshaft portion 65 b and the large diameter shaft 66 a inside the firsthole 160 in the axial direction.

With the reduction in the contact area between the opposing holeportions 90 and 91 and the shaft members 65 and 66, the assemblytolerances at the insertion location are more easily handled. In aconfiguration that provides a surface contact between the shaft members65, 66 and the entire cylindrical inner surface of the circular holes 60a and 61 a, the resistance generated by press fitting of the shaftmembers 65 and 66 tends to change significantly due to a variation inthe tolerances between the shaft members 65 and 66 and the holes 60 aand 61 a. By contrast, in the configuration according to the firstvariation of an embodiment of the present disclosure in which the shaftmembers 65 and 66 contact a part of the inner surface of the hole, thechange in the resistance of the shaft members 65 and 66 to the hole isreduced even with the variation in the same degree of tolerances betweenthe hole and the shaft members 65 and 66. The same advantageous effectsare obtained from the following configurations according to a secondvariation to a fourth variation.

FIGS. 39 and 40 are illustrations of a positioning mechanism accordingto the second variation of an embodiment of the present disclosure. Inthe second variation of the embodiment, the first hole 260 has anopposing hole portion 92 as a substitute for the circular hole 60 aaccording to the above-described embodiment, and the second hole 261 hasan opposing hole portion 93 as a substitute for the circular hole 61 aaccording to the above-described embodiment.

The opposing hole portion 92 of the first hole 260 includes acylindrical portion 92 a having a cylindrical inner surface, and fourplanes 92 b each of which partially short-circuits the inner surface ofthe cylindrical portion 92 a. Each plane 92 b has a planar shape thatextends along the axial direction of the first hole 260. The four planes92 b are disposed at substantially equal angular intervals (90°intervals) in the circumferential direction around the axis of the firsthole 260. Two of the planes 92 b are spaced apart and opposed to eachother in the long direction (the right-to-left direction) of theelongated hole 60 b. The remaining two planes 92 b are spaced apart andopposed to each other in the width direction (the up-to-down direction)of the elongated hole 60 b, being substantially parallel to the plane 60c of the elongated hole 60 b. The width between the opposed planes 92 bin the up-to-down direction is equal to the width between the opposedprotrusions 90 b in the right-to-left direction. The distance betweenthe two planes 92 b opposed to each other in the width direction (theup-to-down direction) of the elongated hole 60 b is longer than thedistance between the pair of planes 60 c in the elongated hole 60 b.

On the lens barrel 11A side, the shaft portion 65 a of the shaft member65 is inserted into the opposing hole portion 92 of the first hole 260.The virtual circle indicated by a two-dot chain in FIG. 39 is anincircle that internally contacts the four projections 92 b of theopposing hole portion 92. That is, the shaft portion 65 a of the shaftmember 65 has a diameter of the circle. In this contact state, the shaftportion 65 a is lightly press-fitted into the opposing hole portion 92.That is, the distance between the opposed planes 92 b is slightlysmaller than the diameter of the shaft portion 65 a at the initialstate. The shaft portion 65 a contacts each of the planes 92 b in alinear region along the axial direction of the first hole 260. The shaftportion 65 a does not contact each of the cylindrical portion 92 a.Accordingly, the contact area between the shaft portion 65 a and theopposing hole portion 92 is reduced, and thus a load imposed byinsertion of the shaft portion 65 a is reduced as compared to theconfiguration in which substantially the entire outer surface of theshaft portion 65 a contacts the inner surface of the hole. Further, sucha configuration that includes the plurality of planes 92 b reduces orprevents tilting of the shaft portion 65 a, and also advantageouslyadvances the shaft portion 65 a inside the first hole 260 in the axialdirection.

On the lens barrel 11B side, the small diameter shaft 66 b of the shaftmember 66 is inserted into the first hole 260. In the opposing holeportion 92, each of the distance between the two planes 92 b opposed toeach other in the right-to-left direction and the distance between thetwo planes 92 b opposed to each other in the up-to-down direction isshorter than the diameter of the small diameter shaft 66 b (the base endsection 66 f and the tip section 66 g). Accordingly, each plane 92 bdoes not hamper the insertion of the small diameter shaft 66 b into thefirst hole 260.

Same as the opposing hole portion 92 of the first hole 260, the opposinghole portion 93 of the second hole 261 includes a cylindrical portion 93a having a cylindrical inner surface, and four planes 92 b each of whichpartially short-circuits the inner surface of the cylindrical portion 92a. The shape (inner diameter) of the cylindrical portion 93 a and thearrangement and shape of each plane 93 b are the same as those of thecylindrical portion 92 a and each plane 92 b of the opposing holeportion 92. The four planes 93 b are disposed at substantially equalangular intervals (90° intervals) in the circumferential directionaround the axis of the second hole 261. Two of the planes 93 b arespaced apart and opposed to each other up-to-down direction, and theremaining two planes 93 b are spaced apart and opposed to each otheralong the right-to-left direction. Each distance between the two opposedplanes 93 b is greater than the diameter of the small diameter hole 61 bof the second hole 261.

On the lens barrel 11A side, the large diameter shaft 66 a of the shaftmember 66 is inserted into the opposing hole portion 93 of the secondhole 261. On the lens barrel 11B side, the shaft portion 65 b of theshaft member 65 is inserted into the opposing hole portion 93 of thesecond hole 261. The virtual circle indicated by a two-dot chain in FIG.39 is an incircle that internally contacts the four projections 93 b ofthe opposing hole portion 93. That is, each of the shaft portion 65 band the large diameter shaft 66 a (the base end section 66 d) of theshaft member 65 has a diameter of the circle. In this contact state,each of the shaft portion 65 b and the large diameter shaft 66 a (thebase end section 66 d) is lightly press-fitted into the opposing holeportion 93. That is, the distance between the opposed planes 93 b isslightly smaller than the diameter of the shaft portion 65 b and thebase end section 66 d at the initial state. The shaft portion 65 b andthe large diameter shaft 66 a (the base end section 66 d) contact eachof the planes 93 b in a linear region along the axial direction of thesecond hole 261. Neither the shaft portion 65 b nor the large diametershaft 66 a contacts the cylindrical portion 93 a. Accordingly, thecontact area of the opposing hole portion 93 contacting the shaftportion 65 b and the large diameter shaft 66 a (the base end section 66d) is reduced, and thus a load imposed by insertion of the shaft portion65 b and the large diameter shaft 66 a (the base end section 66 d) isreduced. Further, such a configuration that includes the plurality ofplanes 93 b reduces or prevents tilting of the shaft portion 65 a, andalso advantageously advances the shaft portion 65 b and the largediameter shaft 66 a inside the second hole 261 in the axial direction.

FIGS. 41 and 42 are illustrations of a positioning mechanism accordingto the third variation of an embodiment of the present disclosure. Inthe third variation of the embodiment, the first hole 360 has anopposing hole portion 94 as a substitute for the circular hole 60 aaccording to the above-described embodiment, and the second hole 361 hasan opposing hole portion 95 as a substitute for the circular hole 61 aaccording to the above-described embodiment.

The opposing hole portion 94 of the second hole 360 has four planes 94a. The four planes 94 a are provided at substantially the same positionsas those of the four planes 92 b of the opposing hole portion 92according to the second variation, and also formed in the samedirections as those of the planes 92 b according to the secondvariation. The third variation differs from the second variation (theopposing hole portions 92) in that the corner portion (including agentle chamfered shape) is formed between two adjacent planes 94 a inthe third variation. In other words, the opposing hole portion 92according to the second variation and the opposing hole portion 94according to the third variation are common in terms of a rectangularhole shape defined by four planes.

As illustrated in FIG. 41, on the lens barrel HA side, the shaft portion65 a of the shaft member 65 is press-fitted into the opposing holeportion 94 of the first hole 360 and internally contacts the four planes94 b. Accordingly, a stable insertion of the shaft member is performedwith a less load on the holes. Further, on the lens barrel 11B side,each plane 94 b of the opposing hole portion 94 does not hamper theinsertion of the small diameter shaft 66 b into the first hole 360.

The opposing hole portion 95 of the second hole 361 has four planes 95a. The four planes 95 a are provided at substantially the same positionsas those of the four planes 93 b of the opposing hole portion 93according to the second variation, and also formed in the samedirections as those of the planes 93 b according to the secondvariation. The third variation differs from the second variation (theopposing hole portions 92) in that the corner portion (including agentle chamfered shape) is formed between two adjacent planes 95 a inthe third variation. In other words, the opposing hole portion 93according to the second variation and the opposing hole portion 95according to the third variation are common in terms of a rectangularhole shape defined by four planes.

As illustrated in FIG. 41, on the lens barrel 11A side, the largediameter shaft 66 a (the base end section 66 d) of the shaft member 65is press-fitted into the opposing hole portion 95 of the second hole 361and internally contacts the four planes 95 a. On the lens barrel 11Bside, the shaft portion 65 b of the shaft member 65 is is press-fittedinto the opposing hole portion 95 of the second hole 361 and internallycontacts the four planes 95 a. Each of the shaft portion 65 b and thelarge diameter shaft 66 a can be stably inserted into the opposing holeportion 95 with a less load.

FIGS. 43 and 44 are illustrations of a positioning mechanism accordingto the fourth variation of an embodiment of the present disclosure. Inthe fourth variation of the embodiment, the first hole 460 has anopposing hole portion 96 as a substitute for the circular hole 60 aaccording to the above-described embodiment, and the second hole 461 hasan opposing hole portion 97 as a substitute for the circular hole 61 aaccording to the above-described embodiment.

The opposing hole portion 96 of the first hole 460 includes acylindrical portion 96 a having a cylindrical inner surface, and threeplanes 96 b each of which partially short-circuits the inner surface ofthe cylindrical portion 96 a. Each plane 96 b has a planar shape thatextends along the axial direction of the first hole 460. The threeplanes 96 b are disposed at substantially equal angular intervals (120°intervals) in the circumferential direction around the axis of the firsthole 460. In other words, the opposing hole portion 96 has asubstantially triangle shape inside defined by three surrounding planes96 b. One of the three planes 96 b, which is disposed at the upper partalong the up-to-down direction, is substantially parallel to the plane60 c of the elongated hole 60 b, and is disposed farther (on the outerdiameter side) from the center of the first hole 460 than the elongatedhole 60 b does. The remaining two planes 96 b are slanted at the sameangle in opposite directions relative to the plane 60 c of the elongatedhole 60 b.

On the lens barrel 11A side, the shaft portion 65 a of the shaft member65 is inserted into the opposing hole portion 96 of the first hole 460.The virtual circle indicated by a two-dot chain in FIG. 43 is anincircle that internally contacts the three planes 96 b of the opposinghole portion 96. That is, the shaft portion 65 a of the shaft member 65has a diameter of the circle. In this contact state, the shaft portion65 a is lightly press-fitted into the opposing hole portion 96. Theshaft portion 65 a contacts each of the planes 962 b in a linear regionalong the axial direction of the first hole 460. The shaft portion 65 adoes not contact each of the cylindrical portion 96 a. Accordingly, thecontact area between the shaft portion 65 a and the opposing holeportion 96 is reduced, and thus a load imposed by insertion of the shaftportion 65 a is reduced as compared to the configuration in whichsubstantially the entire outer surface of the shaft portion 65 acontacts the inner surface of the hole. Further, such a configurationthat includes the plurality of planes 96 b reduces or prevents tiltingof the shaft portion 65 a, and also advantageously advances the shaftportion 65 a inside the first hole 460 in the axial direction.

On the side of the lens barrel 11B side, the small diameter shaft 66 bof the shaft member 66 is inserted into the first hole 460. In theopposing hole portion 96, the space surrounded by three planes 96 b hasa larger diameter than the small diameter shaft 66 b (the base endsection 66 f and the tip section 66 g) does, which prevents each plane96 b from hampering insertion of the small diameter shaft 66 b into thefirst hole 460.

Same as the opposing hole portion 96 of the first hole 460, the opposinghole portion 97 of the second hole 461 includes a cylindrical portion 97a having a cylindrical inner surface, and three planes 97 b each ofwhich partially short-circuits the inner surface of the cylindricalportion 97 a. The shape (inner diameter) of the cylindrical portion 97 aand the arrangement and shape of each plane 97 b are the same as thoseof the cylindrical portion 96 a and each plane 96 b of the opposing holeportion 96. The three planes 97 b are disposed at substantially equalangular intervals (120° intervals) in the circumferential directionaround the axis of the second hole 461. When viewed along the axis ofthe second hole 461, all of the cylindrical portion 97 a and the threeplanes 97 b are located outside the small diameter hole 61 b of thesecond hole 461 (see FIG. 43).

On the lens barrel 11A side, the large diameter shaft 66 a of the shaftmember 66 is inserted into the opposing hole portion 97 of the secondhole 461. On the lens barrel 11B side, the shaft portion 65 b of theshaft member 65 is inserted into the opposing hole portion 97 of thesecond hole 461. The virtual circle indicated by a two-dot chain in FIG.43 is an incircle that internally contacts the three planes 97 b of theopposing hole portion 97. That is, each of the shaft portion 65 b andthe large diameter shaft 66 a (the base end section 66 d) of the shaftmember 65 has a diameter of the circle. In this contact state, each ofthe shaft portion 65 b and the large diameter shaft 66 a (the base endsection 66 d) is lightly press-fitted into the opposing hole portion 97.The shaft portion 65 b and the large diameter shaft 66 a (the base endsection 66 d) contact each of the planes 97 b in a linear region alongthe axial direction of the second hole 461. Neither the shaft portion 65b nor the large diameter shaft 66 a contacts the cylindrical portion 97a. Accordingly, the contact area of the opposing hole portion 97contacting the shaft portion 65 b and the large diameter shaft 66 a (thebase end section 66 d) is reduced, and thus a load imposed by insertionof the shaft portion 65 b and the large diameter shaft 66 a (the baseend section 66 d) is reduced. Further, such a configuration thatincludes the plurality of planes 93 b reduces or prevents tilting of theshaft 67 b, and also advantageously advances the shaft portion 65 b andthe large diameter shaft 66 a inside the second hole 461 in the axialdirection.

In the first to fourth variations (FIGS. 37 to 44), each of the opposinghole portions (90, 91, 92, 93, 94, 95, 96, 97) provided in the firstholes (160, 260, 360, 460) and the second holes (161, 261, 361, 461) isa non-circular hole having inside a plurality of contacts (theprotrusions 90 b and 91 b, and planes 92 b, 93 b, 94 a, 95 a, 96 b, and97 b) on the same virtual circle (the outer periphery of the shafts 65 aand 65 b and the base end section 66 d of the large diameter shaft 66 a,indicated by two-dotted chain lines in FIG. 37). The shafts 65 a and 65b of the shaft member 65 and the base end section 66 d of the largediameter shaft 66 a of the shaft member 66 are supported in contact withthe plurality of contacts of each non-circular hole. As can beunderstood from these variations, the main-reference positioningmechanism according to the embodiments of the present disclosure mayhave a configuration in which each contact of the hole and the shaft hasa non-cylindrical surface.

In the above-described embodiments and variations, the shapes of theopposing hole portions of the first hole and the second hole are thesame, but the internal shapes of the opposing hole portion of the firsthole and the opposing hole portion of the second hole may be differentfrom each other. For example, the circular hole 60 a of theabove-described embodiment may be used as the opposing hole portion ofthe first hole, and one of the opposing hole portions 91, 93, 95, and 97of the above-described variations may be used as the opposing holeportion of the second hole. In this case, the shaft member 65 and theshaft member 66 of the above-described embodiments may be used as is aslong as the diameter of the virtual circle inscribed in the innersurface of the hole is set to be the same between the circular hole 60 aand the opposing hole portions 91, 93, 95, and 97.

The present disclosure is not limited to the above-described embodimentsand variations, and numerous additional and variations are possible inlight of the above teachings. For example, in the above-describedembodiments, the large diameter shaft 66 a and the small diameter shaft66 b, which constitute the sub-reference positioning mechanism, arepartially different in diameter from each other (the large diametershaft 66 a includes the base end section 66 d and the tip section 66 e,and the small diameter shaft 66 b includes the base end section 66 f andthe tip section 66 g). It is also possible to provide a similarstructure to the shaft member 65 constituting the positioning mechanismon the main reference side. The configurations according to theabove-described embodiments causes the shaft members 65 and 66 to bepress-fitted into the first hole 60 (160, 260, 360, 460) and the secondhole 61 (161, 261, 361, 461), which achieves a stable support for thelens barrels 11A and 11B and prevents rattling of the lens barrels 11Aand 11B. Particularly, the flange 65 c of the shaft member 65 and theflange 66 c of the shaft member 66 are not disposed between the lensbarrel 11A and the lens barrel 11B, so as not to hamper the positioningin the front-to-back direction using the contact surfaces 50 and 51.Accordingly, the shaft members 65 and 66 can be press-fitted into thefirst hole 60 (160, 260, 360, 460) and the second hole 61 (161, 261,361, 461). Further, in addition to the press-fitting, the shaft members65 and 66 may be fixed to the first hole 60 (160, 260, 360, 460) and thesecond hole 61 (161, 261, 361, 461) by a fixing member such as adhesive.

In the above-described embodiments and variations (FIGS. 37 to 44), aplurality of configurations of the first hole and the second hole intowhich the shaft member 65 and the shaft member 66 are inserted aredescribed. In some other embodiments, the first hole and the second holemay have other different shapes. For example, the first hole and thesecond hole may have a polygonal shape (hexagonal or the like) whoseinternal shape is other than triangle or square.

The embodiments of the present disclosure are particularly effective inan imaging apparatus in which two imaging units to be combined have theidentical shape. In the above-described embodiments, the lens barrel 11Aand the lens barrel 11B have the identical shape, and the base frames 12of the lens barrel 11A and the lens barrel 11B also has the identicalshape. However, the embodiments of the present disclosure are applicablein optical systems in which two holders (the base frames 12) holding twooptical systems have different shapes and configurations.

In the composite lens barrel 10 according to an embodiment of thepresent disclosure, the optical axis X1 of the lens barrel 11A and theoptical axis X1 of the lens barrel 11B are arranged coaxially. Theconfiguration according to an embodiment of the present disclosure maybe applied to an optical system in which the optical axes of incidentlight from an object in the optical systems are not coaxially arrangedas long as the two optical systems are disposed symmetrically.

In the above-described embodiments and variations, cases in which twolens barrels 11A and 11B including the wide-angle lens systems A and Band the image sensors AI and BI (two imaging units) are combined aredescribed. The optical system according to the embodiments of thepresent disclosure may be applied to a configuration that positions twoholders by using the contact surfaces without the image sensors AI andBI disposed in the lens barrels 11A and 11B (that is, the image sensorsAI and BI are separate from the optical system).

In the above-described embodiments, the composite lens barrel 10 or theimaging apparatus 80 generate a spherical image. However, no limitationis intended thereby, and an image obtained by the optical systems may bean image other than a spherical image, such as a panoramic imageobtained by photographing 360 degrees only in a horizontal plane.

Numerous additional modifications and variations are possible in lightof the above teachings. It is therefore to be understood that, withinthe scope of the above teachings, the present disclosure may bepracticed otherwise than as specifically described herein. With someembodiments having thus been described, it will be obvious that the samemay be varied in many ways. Such variations are not to be regarded as adeparture from the scope of the present disclosure and appended claims,and all such modifications are intended to be included within the scopeof the present disclosure and appended claims.

What is claimed is:
 1. An optical system comprising: two imaging opticalsystems disposed symmetrically with each other; two holders includingone holder to hold one imaging optical system, and other holder to holdthe other one imaging optical system, each holder having a first holeand a second hole; and two shaft members including a first shaft memberand a second shaft member, the two shaft members disposed between thetwo holders, the two holders being disposed such that the first holesare opposed to the second holes, the first shaft member being held bythe first hole of the one holder, and the second shaft member being heldby the second hole of the one holder, the first shaft member beingdisposed in the second hole of the other holder with a movement of thefirst shaft member restricted in each direction perpendicular to adirection in which the first holes are opposed to the second holes, thesecond shaft member being disposed in the first hole of the other holderwith the second shaft member movable in only a certain direction withina plane perpendicular to the direction in which the first holes areopposed to the second holes.
 2. The optical system according to claim 1,wherein each of the first hole and the second hole has an opposing holeportion one opposing hole portion of the first hole is opposed to theother opposing hole portion of the second hole when the first hole isopposed to the second hole, the first hole further has an elongated holecommunicable with the one opposing hole portion and having a longdirection along a direction perpendicular to an axial direction of thefirst hole, and the second shaft is movable relative to the elongatedhole in the long direction with a movement restricted along the axialdirection of the first hole.
 3. The optical system according to claim 2,wherein the first shaft member includes a pair of insertion sectionshaving the same diameter and a shape symmetrical to each other along theaxial direction, and the opposing hole portion of each of the first holeand the second hole has an internal shape that contacts and supports acorresponding one of the insertion sections of the first shaft member.4. The optical system according to claim 3, wherein a width of theelongated hole in the axial direction of the first hole is smaller thana diameter of a virtual circle that inscribes the opposing hole portionof each of the first hole and the second hole, and the second shaftmember includes a first shaft and a second shaft, the first shaftdisposed in and supported by the opposing hole portion of the secondhole, and the second shaft disposed in and supported by the elongatedhole.
 5. The optical system according to claim 4, wherein a length ofthe first shaft of the second shaft member in an axial direction of thefirst shaft is longer than a length of the opposing hole portion of thefirst hole.
 6. The optical system according to claim 2, wherein at leastone of the one opposing hole portion of the first hole and the otheropposing hole portion of the second hole is a circular hole having acylindrical inner surface.
 7. The optical system according to claim 2,wherein at least one of the one opposing hole portion of the first holeand the other opposing hole portion of the second hole is a non-circularhole having a plurality of contacts on a virtual circle inside.
 8. Theoptical system according to claim 1, wherein at least one of the firstshaft member and the second shaft member is press-fitted into at leastone of the first hole and the second hole.
 9. The optical systemaccording to claim 1, wherein at least one of the first shaft member andthe second shaft member further includes a restriction part configuredto restrict a maximum amount of insertion of a corresponding one of thefirst shaft member and the second shaft member into the first hole andthe second hole.
 10. The optical system according to claim 1, whereinanother member other than the first shaft member and the second shaftmember is positioned by at least one of the first hole and the secondhole.
 11. An imaging apparatus comprising: the optical system accordingto claim 1; and two image sensors to form images captured by the twoimaging optical systems, so as to combine the formed images to generateone image.